Jeep TJ Axle Upgrades HPD30/Rubicon D44

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Jeep TJ Axle Upgrades HPD30/Rubicon D44

Postby KCStudly » Wed Oct 19, 2016 1:15 pm

One of my tow vehicle's is an '03 Jeep TJ Wrangler Sport with an NV3550 5-spd manual trans, Dana 30 front end and the dreaded Dana 35 rear end. As we approach 200k miles on the odometer the D35 started to make loud noise on deceleration, likely indicating a pinion bearing failure and imminent doom. Sure enough, she done blow'd up last week and I have to take a pause from my camper build in order to take care of this business.

The D35 has a bad reputation among 4-wheelers as being weak and failure prone when asked to do much more than stock duty, such as towing or rock crawling. Also, ever since putting the spacer lift and 31 inch tires on, the 3.07 gear ratio just doesn't cut it; high gear is all but useless except when going down hill.

So rather than fixing the D35 turd, I searched my regional CL and found an '04 Dana 44 out of a TJ Rubicon (the last year before changes were made for the JK's). This rear axle has a broken OEM locker from a front D44 out of another TJ Rubicon (broken spiders; there are internet debates about the strengths and weaknesses of the OEM front open diff/lockers vs. the rear lockers with anti-slip diff, with the locker feature in either being selectable). This axle has 4.10 gears (which are ideal for my tire size and towing), and also came with the original anti-slip/locker, another set of 4.10 gears, a set up kit (new bearings, shims, seals, etc.) and a factory air pump (the factory lockers us low pressure pumps... about 5 psi... to activate, unlike aftermarket air lockers).

Due to my mild lift I will most likely have to have the driveshaft shortened to suit the new axle's longer pinon shaft.

I'm about to go thru the process of overhauling and doing a gear setup on the replacement axle and was wondering if there was any interest here in seeing how I go about it; or is that too far off topic for a camper forum? I figure it is relevant to my story because it is an upgrade that I need to do for more reliable towing, but others might not be as interested.

I'd be happy to take some pics along the way, but probably won't go into all of the little details (unless I can't help myself :R ).

What do you think?
Last edited by KCStudly on Fri Nov 18, 2016 8:38 pm, edited 3 times in total.
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Re: TJ Rubicon Dana 44 Rebuild

Postby aggie79 » Wed Oct 19, 2016 1:41 pm

Please show pictures, KC! I love all the gearhead stuff I can see even though it's been a few decades since I've turned any wrenches in earnest.


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Re: TJ Rubicon Dana 44 Rebuild

Postby KCStudly » Wed Oct 19, 2016 9:58 pm

Okay, Tom has spoken and that is good enough for me.

No pics tonight... tough to take with disposable glove and gear lube on hands. I will do better.

So more back story. Thursday I took off work to do the final pack out of our pumpkin throwing ballista, so slept in a bit. Was awoken by the answering machine. It was my wife informing me that the Jeep "was making a horrible noise and not acting right". She had made it out to the main road before turning around and coming back to take my car to work.

Sudden realization that I was coming into a long busy weekend getting off to the chunk and was now stuck at home.

For some incalculable female reasoning she had parked the Jeep in the street in front of the neighbor's house instead of in the driveway. Made more sense when I went to do a test drive and found that it wouldn't run in reverse, just gear teeth skipping past each other noises; but it would run under load in first. Coast was loud grinding noises. I reasoned that the helical cut gears were still meshing as the gears cupped into one another, managing to glide over the broken teeth under load, but pushed apart and defected when the helix ran in the opposite direction, or didn't have enough load to stay engaged. We'll find out when I crack the cover off in order to pull the C-clips so that I can harvest the drum brakes off of the D35.

Anyway, I was able to limp it around our little neighborhood and get it into the driveway. Later, Karl came and got me and we finished preparing for the chunk. After we got back from the chunk, Monday, Karl and I dragged my flat bed low deck car trailer out, spent a huge effort getting the drum brakes freed up on it (a whole other story) and hauled the Jeep over to his place where I could have a flat place to do the swap, and I think he really wants to be a part of this anyway, so why look a gift horse in the mouth?

Since the Jeep would not go in reverse in 2-Hi, I put it into 4-Lo to be able to back it out of the driveway and drive it up onto the trailer. Despite having built the car trailer many years ago, it has never been towed or used to haul anything (another long story that has been told), so it was actually a pleasure to see it in use; towed very well and worked exactly as designed. We also loaded up the D44 and all of the related parts.

Tuesday was back to work at the day job.

Tonight we dragged the axle in off the trailer. I slid under the Jeep, still on the trailer, and spent a few minutes squirting PB Blaster on any of the suspension fasteners, brake fittings, anti-sway bar bolts, etc. that I could get a bead on w/o jacking her up; all to help soften things up for future reference.

Then we started tearing down the replacement axle. I used some label tags to identify the left and right axles (turns out they are slightly different lengths, but better to keep track… if they were the same you don’t want to suddenly twist them in the opposite direction than they were already being loaded by inadvertently installing them on the opposite side… as it is, having them labelled will avoid confusion). More tags for the carrier bearing races and outer shims, the pinon preload (outer) shims, and the pinion depth (inner) shims. During tear down we found several differential spider gear teeth floating around, confirming the previous failure diagnosis, the reason the seller had pulled the unit and had disclosed during the sale. Also, the pinion seal contact surface on the drive yoke (the part that the drive shaft u-joint bolts to) is pretty worn, so that will likely be replaced.

Next we used a brass drift, actually a large piece of bronze round bar left over from one of Karl’s high end handrail projects, to drive the outer pinion bearing and seal out, then both pinion bearing races (bearing “cups”).

As mentioned elsewhere, the ’04 Rubicons (and perhaps others) have disc rear brakes, while my D35 has drums. The “new” axle didn’t come with any brake parts. While the wheel bolt pattern is the same I can’t be sure that my existing 15 inch American Racing Mojave wheels will clear the disc brakes, don’t want to have to buy new wheels (including the matching trailer wheels for TPCE that I have already bought), and don’t really want to spend more money to upgrade to disc when we just had the drum brakes replaced not too long ago. So a little research found that the only difference is the axle retaining plates. The disc brake retaining plate allows for the thicker caliper mounting bracket while the drum brake retaining plate allows for the thinner brake shoe backing plate. Otherwise the D35 and D44 drum brakes should be interchangeable. So when I ordered new axle bearings and seals I ordered them as kits that include the proper drum brake style bearing retaining plates. That way, since I wasn’t sure what sequence the rebuild and swap process would take, I would have them in hand when I press the new bearings on, without having to tear down the old axle first.

Lastly, I pulled all of the extra parts out to organize and compare; packed everything in the car to take to work with me tomorrow. After work tomorrow I’ll use the press to pull the old bearings off. Of the ones I can manage not to damage I plan to use the die grinder with a stone bit to open up the clearance so that they can be used as a “setup” bearing set; by making them a smooth slip fit you can go through the whole setup process, through multiple test assemblies and shim adjustments getting the pinion depth, backlash and mesh patterns just right before committing to pressing the new bearings on with their interference fit. This helps prevent damage to the new bearings and seating surfaces by avoiding multiple pressing operations (some of which are impossible to avoid damage due to the lack of special factory tooling and the lack of clearance for a standard bearing splitter in way of the locker apply piston).

I’m also considering making some aluminum drivers to seat the new bearing cups (outer races) into the housing. These would drive the races more squarely from their whole diameter rather than relying on a point load from a brass punch with more of a chance to drive the races askew.
Last edited by KCStudly on Sun Oct 23, 2016 7:55 am, edited 1 time in total.
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Re: TJ Rubicon Dana 44 Rebuild

Postby KCStudly » Sat Oct 22, 2016 9:56 pm

So I have taken a few pics, but being that I have been working at the day job shop, I more or less have been just trying to get it done and haven’t been taking as many pics as would be needed to do a blow by blow instruction. Just want to get it done. I’ll post some pics eventually.

Last night, after punching out, I used a hand truck to haul all of the parts boxes into the shop and got started. I had hoped to be able to pull the inner pinion bearing off of the 5.13 pinion intact so that I could hone the ID out and use it as a slip fit setup bearing. Unfortunately there was no room to get a bearing splitter under the inner race. I tried to hook the bearing splitter under the rollers, hoping that it would press off easily without damaging the roller cage, but that was not the case. The cage blew out, so I removed it and all of the rollers allowing me to position the splitter under the lip of the small end of the inner race cone. The arbor press wasn’t enough so I had to use the hydraulic press. Even though I wouldn’t be using the 5.13 gear set, that got me the original pinion depth shim from under the bearing (0.060 thk) which I can use as a baseline for setting up the 4.10 gear set.

Next up was removing the Timken carrier bearing “cones” (inner races and roller bearing cage assemblies) from the TFS locker carrier. They looked to be in pretty good shape, but the seller didn’t include the “cups” (outer races), and even if he had I couldn’t have been sure that they had stayed with their respective sides; and it is just good practice to replace all of the bearings whenever you get this deep into it. Plus, new bearings are included in the setup kit that was included in the deal.

Getting the carrier bearings off was another story. On one side, the “gear side”, it was the same deal as the pinion; there just was not enough space under the bearing to get a splitter in to catch the edge of the inner race. There are indentations that would accept the jaws a specialty puller, but you would need a puller with extra long and narrow jaws in order to reach past the rollers and cages, and to fit into the recesses provided. Fortunately the Rubicon carriers are shimmed outside of the bearings, so there is no need for setup bearings on the carrier, so no need to try and save these.

I wrapped the carrier in shop rags to keep crud out; used the Dremel tool with a cut off disc to cut the bearing cages; and then a flat bladed screwdriver to pry the cages away and remove all of the rollers. Next I used the cut off wheel to score most of the way thru the inner races on two opposing sides. I used a little spit to dampen the rags under the cut so that I didn’t start a fire… oh my!

A few… okay several good hard whacks with a cold chisel in the scores eventually cracked the races, relieving the interference press, allowing them to be pulled off with the bearing splitter and a large 2-jaw puller.

Once the “opposite side” (from the gear) bearing cage and rollers were removed I could remove the locker apply piston assembly (that prevented the use of the bearing splitter under the bearing) and wipe that down with shop rags; needed to be sure to reinstall that prior to pressing the new bearing on.

That all took surprisingly longer than it sounds like it should have, and by then I was getting to the end of my rope for the night.

Today I started out by cleaning the 4.10 gear set that I had chosen. They both seemed to be about the same, in good condition, so I can’t really say why I chose one set over the other; but after washing the ring and pinion in the “gunk tank” (parts washer), blowing out all of the threaded holes, and swabbing out all of the threads with thread locker solvent (a tedious task), I found that not only did the ring gear drop right onto the carrier with no interference, but it also had a little “wink” (I could just perceive a little relative movement between the carrier and gear when pushing it from side to side). No bueno. Ring gears typically are a slight interference fit to their carriers and usually have to be tapped on with a dead blow hammer, warmed to fit, or even drawn on by jacking bolts at the threads.

So back to the gunk tank with the other set to see if that fits better. This time I checked the fit before going thru the effort to clean all the threads. This ring gear dropped right on, too, but there was no perceptible wink, so I’m going with it.

Now the D44 axles have a gear split at the 3.73 ratio. So 3.73 and up (down numerically) gear ratios use one carrier offset, while 3.92 and down (up numerically) gears uses another. This is because as the ratio goes up numerically the pinion diameter gets smaller, so the ring gear has to move closer; and the material the ring gears are made out of is far more expensive in mass production than it costs to create separate parts for the related carriers (since moving the ring gear mounting flange on the carrier doesn’t really add any extra material).

This is where it gets confusing. The 5.13 ratio gear mounted to the open/locker carrier has a spacer under the ring gear, and yet that ring gear appears to be thicker than the 4.10 ring gears. In a way this makes sense, since the taller ratio has a smaller pinion, so even at the same carrier offset the 5.13 gear should be thicker… but why would a Rubicon front carrier, that all have 4.10 gear ratios, need a spacer?

They make “thick” gear sets that allow you to run lower ratio (higher numerically) gears on a 3.73 and up carrier, or you can run a shim like the one I’m seeing; but I’m not aware of any Rubicon lockers that came from the factory with 3.73 or higher gears.

So when it came time to apply the relatively permanent red thread locking compound and torque the “torque to yield” ring gear bolts I was hesitant to do it. My logic was that since I was supposedly reestablishing the factory arrangement using factory parts, and they would never use a gear spacer as original equipment, I should be okay without the spacer. On the other hand, if any of these parts weren’t as advertised, when I go to do the initial fitting I might find that I do need the spacer, and then I would wish that I hadn’t used the red thread locker, nor have torqued the ring gear bolts fully.

Internet research was inconclusive, so I decided to run the bolts up dry to only 30 lbs-ft (on a 45 to 60 lbs-ft spec… one source say 55 lbs-ft with red locking compound). Since the ring gear is an easy fit, it won’t be any trouble to pop it off later if the spacer is needed, or I can just pull the bolts, apply the locking compound and torque to spec. The carrier will likely be going in and out several times during setup anyway.

Making sure to reinstall the locker apply piston first, I used a little gear lube and the arbor press to install the new carrier bearings; making sure to tag and save the outer races respectively (“gear side” and “opposite side”) so as not to mix match the sets (might not matter with new bearings, but why take a chance?).

I think I mentioned that the pinion yoke showed signs of wear in way of the pinion lip seal. Rather than monkey with dressing this area and hoping that the seal still has enough “set” (seal tension), or installing a Speedi-Sleeve, I decided to get a replacement. But first it seemed like a good idea to confirm if the Rubicon D44 and non-Rubicon D35 use the same U-joint. They don’t. The D35 uses a 1310 while the D44 uses a 1330. <edit> The 1330 is bigger across from end to end on its caps; turns out they both have 1-1/16 diameter caps. <end edit>

I have options. I could buy a new pinion yoke that would accept the 1310 u-joint, but I consider that to be a non-upgrade, not befitting the advantages of the D44. I could replace the existing pinion yoke and run a hybrid U-joint that is sized for 1330 on one of its shafts and 1310 on the other (yeah, maybe); or, if I do have to modify the drive shaft, I could upgrade the rear yoke to a 1330 size and get the full benefit of the larger U-joint size, at least at the rear where the driveline is more susceptible to trail damage.

One more thing; the stock U-joint fasteners are of the bolt and strap type where the pinion yoke has threaded holes. The U-bolt style of U-joint fasteners that wrap the U-joint bearing cups and pass thru clear holes in the pinion yoke with nuts on the back side are considered to be superior, so I ordered that version of the 1330 yoke with new U-bolt fasteners. Once I get the axle fit and flex the suspension out, I’ll measure for the driveshaft and decide on the U-joint. If the shaft has to be modified I’ll upgrade to the full 1330 joint; if not I’ll run the hybrid joint.

Finally, when we drove the pinion bearing cups out we just used the big bronze drift, but when we reinstall the new bearing cups I’d like to use a bearing race driver. This amounts to an aluminum disc, sized to the bearing, on an arbor so that it can be driven squarely. The disc spreads the force out on the race and the relatively soft aluminum dampens the driving force, helping to protect the harder steel race from damage. I found a chunk of 3 inch aluminum round bar; chucked it in the lathe; faced one end; turned the OD true to just under the inner pinion bearing OD (3 inch nominal); turned a stepped shoulder to guide the big end of the cup; turned the rest of the end to guide the ID of the small end of the cup; centered and successively drilled thru to 37/64 inch for the 5/8-18UNF thread of the big slide hammer shaft; and tapped thru using a live center in the tailstock to guide the tap (just turning the tap with a wrench by hand on the lathe).

Next I turned the piece around in the chuck; faced the other side; turned part of the OD back to suit the outer pinion bearing OD (2-7/8 nominal, same as the axle bearing cups); turned a similar step sized to slip into the big end of the cup (about 2-1/2 inch); turned the end to slip thru the small end of the outer bearing cup (a little under 2-1/8 inch, hopefully compatible with the ID of the axle bearing cups… didn’t have those with me at the time, but can modify the tool again if need be); and did a final deburr. I’m very happy with the way this turned out and will post a pic of it in use when the time comes.

I also borrowed the big slide hammer from work for tomorrow. I plan to pull the old axle bearing cups out of the housing and use the above tool to install the new pinion bearing races.

I tried to source another inner pinion bearing locally, but didn’t spend too much time before giving up. I could spend $118 on a dedicated setup bearing, or just buy a standard bearing for substantially less and make my own. I’ll just modify the one in the setup kit for now and source a replacement during the week.

I did pick up enough gear lube to fill the diff (2 quarts) and do an oil change after initial break in (2 additional quarts), as well as a big squirt bottle of degreaser/cleaner to clean the housing out.

That’s enough for now, more work tomorrow.
Last edited by KCStudly on Sat Nov 05, 2016 9:44 pm, edited 1 time in total.
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Re: TJ Rubicon Dana 44 Rebuild

Postby aggie79 » Sun Oct 23, 2016 12:10 pm

Wow KC! I'm tired from just reading the thread. Thank you for the detailed explanation.


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Re: TJ Rubicon Dana 44 Rebuild

Postby KCStudly » Sun Oct 23, 2016 11:55 pm

Too much information? Well maybe this is something that I have always had great respect for, but never had the confidence to attempt myself until now. I’ve been a gearhead most of my life but haven’t had the experience, necessary equipment, or need until now; so why not dive right in? I guess there is some latent confidence from my experience rebuilding mixing equipment and working with truly professional machinists that I just want to share out of a sense of pride. On the other hand it could be doubt. I mean, this still seems new to me. The mixer equipment is somewhat forgiving and frequently maintained, so the level of precision required to obtain a long gear life, quiet operation, and reliable service in this application is a step above for me. Who else to share with but interested friends? Even if they are internet friends, they are still interested friends, right?

Maybe it is just you and me, Tom?

No matter, but yes, it is a lot of work that requires a good deal of attention to details, so I am confident that I can pull it off!

Finally some pics! Catching up first, this is the TFS locker (with worm gear pinions to provide anti-slip traction when unlocked). You can see how I have already removed the cage and rollers from the ‘opposite side’ carrier race, and how the locker apply piston assembly can be removed.
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Here is the apply piston after wiping it down. The bolt flanges get pinched between the opposite side carrier bearing cap bolt washers and cap and the air tube connects via molded rubber air tube thru a bulkhead fitting in the housing.
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This tin flange moves axially from the thrust when the apply piston bladder inflates, engaging the locker mechanism. The rim of the tin flange also engages the button on the locker engage switch plunger, providing power to light an indicator on the dash telling the operator that the locker has engaged.
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This was the first puller setup that I tried, but it was woefully under sized. Still, you can see where the jaws are grabbing under the lip of the inner race, and how I have placed an aluminum puck over the axle hole to give the puller something to jack against (the jacking thread is hidden behind the middle jaw). I didn’t take many additional pictures of this operation after this, but the solution ended up using a larger bearing splitter grabbing the same lip, and a much bigger 2-jaw puller pulling on the bearing splitter after adding the reliefs in the inner race.
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Part of the solution was adding relief cuts into the race and chiseling a break to remove the interference. (Also note that I am using aluminum soft jaws and/or scraps of aluminum to clamp the carrier safely in the vise.)
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Back at Karl’s today, the previous owner dragged this rearend over a few rocks. Also note the square drive drain plug.
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The dragging raised a burr under the edge of the diff cover. Here I have started to remove the burr using a bastard cut flat file, as evident by the shiny line around the edge.
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Burr removed.
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Here’s a first look inside of the housing prior to cleaning. The D44 is recognizable by the warped stop sign hexagonal shape. Note the air tube barb on the upper right hand side; below that is the mushroom headed stem of the locker engage indicator switch; and below that is the pinion inner bearing race seat.
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Here’s a little closer look at the air tube and locker switch shaft.
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Here’s a close up of the pinion inner bearing cup seat, and something I was not happy to see. Prior activity punching out a race disturbed the cast metal around the bore causing a raised burr (from about 8:30 to 12:30 clockwise in this pic). I could tell that this was not from Karl and me driving the latest race out because the burr tips were all flattened from the last race crushing them in service. No beuno. Raised burs here would tend to cock the race, and, as the burr settles in under the point load, would tend to allow the pinion mesh with the ring gear to change, increasing clearances (bad), and also affecting the pinion bearing preload (loosening the preset between the inner and outer pinion bearings… bad).
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I decided to let that simmer in my thoughts, considering my options while I worked on cleaning up the housing and the associated small parts, including the carrier bearing caps, fasteners, and diff cover. Repair options included doing nothing (unacceptable!); bringing the housing to work and having one of the qualified machinist set it up and take a cleaning pass (potentially altering the pinion depth baseline… not a super big deal, but time consuming and somewhat risky); or hand working the raised material down.

I decided to also busy myself making a square drive wrench to turn the drain and fill plugs out (never mind my mild embarrassment when Karl returned and reminded me that I could have just used a 3/8 drive socket extension on a ratchet…oh well). All I could find in the drop rack was a piece of 1/2 inch square bar. I cut slivers off two sides using the bandsaw and bent the end using the break press feature on the iron worker. It only took a few minutes and worked well in the end, so not a total loss.
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I had picked up a large squirt bottle of cleaner/degreaser and spent a great deal of time ragging out the housing trying to get all of the metal debris from the broken spider gears. It seemed to just keep coming. Before getting too far along Karl helped me decide to hand work the problem area of the inner pinion bearing seat. Rather than just rubbing on it with a scrap of sandpaper and risking altering the bearing bore and/or chasing highs and lows altering the seat, I made a hard sanding block to fit half of the bore (allowing me to still hold the block with my fingers down in the hole).
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I took the raised stuff down until it started to clean the phonographic tool marks from the original machining and no farther. The burrs still look a little high in this pic, but I have been bitten before by cleaning down into the phonographic marks and losing a proper fit. It is certainly an improvement from what it was and I’m confident that I didn’t make it worse.
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Not sure if you can see the difference, but here is the housing after thoroughly cleaning.
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To clean out the axle tubes I wadded up a shop rag soaked with the degreaser, stuffed it into the tube from the center, and pushed it thru using the broom handle from the opposite side.
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This took several passes, a lot of spraying, and the compressed air gun to shoot the rag lint out, but eventually I got it to where no more metal flakes appeared (the dark marks inside the tubes are discoloration from where the suspension brackets were welded onto the outside). I also wire brushed the ends of the tube flanges and bearing retainer stud threads.
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Here’s what’s left of the old inner pinion bearing and the aluminum driver that I mentioned.
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Starting the new inner pinion bearing race into the housing bore.
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Driving the inner pinion bearing race. The weight slug on the slide hammer was too big around and would have hit the carrier bearing saddle, so I just used a ball peen hammer on the end of the slide hammer shaft and it worked fine.
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Here you can see the seated race (at the bottom of pic) as well as a better pic of the locker indicator switch shaft.
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One of the tricks to dealing with these rear ends is avoiding damaging the switch shaft. The switch shaft must be extended when the carrier is dropped in otherwise the disc might not engage the shaft properly and may even break it. The trick is to wedge something under the button of the shaft to hold it in the extended position, and yet have a lanyard attached so that the wedge can be retrieved w/o becoming lost in the housing. A common method is to tie a string around a length of small diameter dowel, however, I did not have any string handy, nor dowel of the proper diameter. So I used a piece of steel tube, similar to brake line, cut in half lengthwise and to the proper length. I deburred this thoroughly, drilled a small 1/16 hole in the middle, and fashioned a piece of welding wire to act as a lanyard hooked over the outside of the housing.
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This allowed me to drop (more correctly, to place) the carrier, with 4.10 ring gear temporarily bolted and carrier bearing cups, into the housing in order to measure the side thrust clearance.
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The Spicer factory manual for the “generic” D44 says to pick and mark one of the ring gear bolts, and use a flat surface thereon to indicate off of. It also says to repeat this measurement until you get a consistent result within 0.002 inch. Well this is pretty ridiculous as there are quite a few raised markings on the bolt heads and the rest is just not that flat. However, on the locker case there are a couple of machine turned surfaces, so I used one of those instead. This gave a very consistent 0.002 runout when checked all the way around (rotating the carrier past the indicator) and 0.001 repeat on zero after thrusting the carrier back and forth, using a couple of flat blade screwdrivers to reach down into the gap at the bearing race preloading it in either direction. In this pic of the ‘opposite’ side you can see the ring gear on the left; the shiny part of the carrier cap that holds the differential worm gears and other magic inside; the locker flange and apply piston; the shiny outer race of the opposite side carrier bearing; and the thrust gap between that and the end of the passenger side axle tube boss. It is this gap that we are trying to accurately measure.
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This measurement gives us the total carrier shim stack that will be divided on either side once we add the pinion and determine how this clearance needs to be divided. In order to preload the bearings and prevent the gears from flexing apart, we need to add between 0.010 and 0.015 inch extra shim (the factory manual calls for 0.015 inch all added to the opposite side, thus splitting the difference and providing about 0.0075 lash; while other internet sources allow 0.010). The indicator indicated 0.258 total thrust. I measured the carrier bearing shims that came out of the 5.13 gear setup and found them to be 0.130 on the gear side and 0.140 on the opposite side, which totals at 0.270 inch, or about 0.012 inch preload; right in range.

The actual shim thickness for either side of the carrier will be determined once the pinion has been installed. We’ll repeat this measurement with the ring gear thrust up against the pinion and compare the difference.

Assuming that we get the pinion depth set right the first time (ha ha), we should get proper backlash, and a good mesh pattern; then we can set the final pinion preload. More likely, the pattern will be off and we will have to adjust the pinion depth shim (hence the need for an easily removable inner pinion setup bearing), which will throw the carrier shims off. And so we will iterate until all of these factors are fat, dumb and happy. There is no room for TLAR here; it must be more or less exact!
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Re: TJ Rubicon Dana 44 Rebuild

Postby aggie79 » Tue Oct 25, 2016 3:55 pm

You're doing a fantastic job KC. That locker setup is a lot more complicated than the 12- and 10-bolt position-trac rear ends that I worked on in the 70s! BTW, I happen to be in Hawaii at this time for my stepson's wedding and have enjoyed your reading your rebuild as I lay in the shade near the beach.


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Re: TJ Rubicon Dana 44 Rebuild

Postby KCStudly » Tue Oct 25, 2016 8:43 pm

Nice! I'm with you there in spirit! :D

They make special setup bearings for this kind of work. They come honed out so that they are a slip fit, making easier to slip on and off without having to use a press while working out all of the shim sizes. For the D44 inner pinion bearing they cost about $120; a lot more than the cost of the standard bearing (around $30-$40).

Several internet accounts claim that it takes only a few minutes to hone out a standard bearing.

So I picked up another 31594 Timken (cone) at a bargain basement price from surplus new/old stock. It had a different outer race (cup) than the inner pinion bearing, but I was only interested in the cone.

Also swung by the house and got all of my torque wrenches; 4 of them. I need to take a closer look at their ranges, but I don’t think any of them will cover the low lbs-in range needed for the pinion preload reading; you need a beam or dial style for that as a ‘click’ type won’t work for a running reading). I have a large 1/2 inch drive click style that may only go up to 175 lbs-ft (need to look; the pinion nut requires the 200-220 lbs-ft; if not Karl may have a larger one or I can borrow the one from work); a 3/8 click that is probably just right for the ring gear bolts and carrier bearing caps (55 and 60 lbs-ft, respectively); a 3/8 beam style that is not sensitive enough for the pinion preload setting of 10 lbs-in (however Doug at work thinks he has one and will loan it to me); and finally a 1/4 drive beam style that goes to 60 oz-in. Yes ounce-inches, but that is still less than 4 lbs-in.

But the real reason I went by the house was to get my little brake cylinder hone. Back in the day when I was just a struggling kid I couldn’t afford to just spend money on car parts willy-nilly, so rather than spend $60 for 4 new wheel cylinders, we would buy rubber rebuild kits for a few bucks and spend $15 on the wheel cylinder hone to restore our old ones. It seems foolish now at $15 a wheel because half the time the cylinders were so pitted with rust that they couldn’t be saved, but sometimes you have to do what you have to do.

The plan was to spend a few minutes honing out the 31594 to make it a slip fit onto the pinion, thus creating a homemade setup bearing (only used to set the pinion depth, making it easier to change shims until you get it just right, then just press the unaltered bearing on once at the end).

Not knowing how quickly the hone would cut, I set the tension low, lubed with some WD40 and only ran the hone briefly before wiping and checking. Here is the bearing clamped in the smooth jaws of the mill vise and the hone with its flexible shaft chucked in the cordless drill.
Image

Here it is in use before adding the emery strip.
Image

No change. I did this a few more times. I could see the metal silt coming off, but the calipers where only indicating minute change (less than the variation in my readings… maybe 0.0001’s on 0.001 graduations. The calipers I was using didn’t agree from inside to outside measurements; I was getting 1.374 OD on the pinion and 1.376 ID on the bearing, but it should be at least a 0.001 interference, perhaps even a bit more; so I figured that the calipers were either off, or just really not the best way to measure bores accurately. Still they should help show relative changes.

So I cut a strip of coarser sander belt, pinned it to one of the shoes of the hone, wrapped it around and cranked the tension up all the way. I estimate that I did about 10 sessions honing for perhaps 2 min at a time (until my wrists were tired from squeezing the trigger on the drill motor and oscillating the hone back and forth), and then wiping away the silt, cleaning the sandpaper clogs and checking progress. So an hour later I may have seen a change of about 0.0015 inch… and the bearing would still not slip onto the pinion.

That $120 wasn’t looking so bad at the moment, but I will get there eventually.

Today I grabbed a die grinder stone out of my kit at work and tomorrow I may try chucking the edge of the race in the lathe while using the hard stone to buzz it out a little quicker.
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Re: TJ Rubicon Dana 44 Rebuild

Postby Philip » Tue Oct 25, 2016 10:32 pm

aggie isn't the only watching.

Ok looking into the case. The left (driver) side carrier outer bearing race looked to be turning a little. It is a known problem with all Dana's from my experience of having rebuilt many. If you look at the right side bearing you don't see a witness mark in it.

What I do in a case like that is to remove about .005" off the mounting block face.

You see this problem a lot on the Dana 70's used behind the diesel trucks.

Another to do item before opening a Dana axle. Run the bill of material number threw the Dana website. If that number does not cross. Get ready for some fun. Dana did some lets say shaddy stuff.
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Re: TJ Rubicon Dana 44 Rebuild

Postby KCStudly » Wed Oct 26, 2016 6:32 am

Thanks for the tip. I'll take a closer look at that saddle tonight, but I didn't see anything that looked obvious. I think the dark line in the pic is just staining, not a scorch or score mark. To me, in the pics, the right/passenger side looks rougher, but again, in person, it doesn't look like anything was spinning there either (maybe my eye is not as well trained as yours?). Both of the old carrier bearing races look fine with no discoloration on the outer diameters (just tell-tale grey ghosting on the inside from all of the fine metal debris that was floating around from the broken spider gears).
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Re: TJ Rubicon Dana 44 Rebuild

Postby Philip » Wed Oct 26, 2016 8:19 am

Look at the pic of the carrier pockets. If you look close at the pic. The spot the outer race sets has more shine than the orignal boring marks. That tells me the outer races have been turning. I don't mean spinning. Just a light turning from a loose factory tolerance fit.

The bore still looks good. Just tighten the hold down crush a little.

When checking side play on the carrier I use the back side of the ring gear as the measure point. Also spin the carrier and check the run out on the ring gear mounting point.
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Re: TJ Rubicon Dana 44 Rebuild

Postby KCStudly » Wed Oct 26, 2016 10:20 am

Okay, so you're suggesting lapping a couple thou off of the pads on the carrier bearing caps? I think that would be easier than trying to set the housing up in a mill in order to skim cut the lands on the housing saddles. No disrespect, and I certainly appreciate the advice of some one with more experience, but I'm still not convinced that we're not just seeing where the tooling marks have been compressed by assembly forces and load in use, rather than any relative motion. I wish you could see it in person to confirm; I will try to get better pictures tonight.

When you say to check the runout on the gear mounting face, do you mean thrust on the carrier itself w/o the gear? ... or radial run out on the OD lip of the carrier? As you can see in the pics, there is no continuous machined surface on the bolt side of the carrier, except closer to the center line on the locker assembly caps, just the bolt spot faces, and not really enough of the gear hanging off the outside edge to get it with the plunger style indicator. I might be able to catch enough of the gear edge with a last word indicator and will look at that.

I agree that checking the thrust run out further out would be more accurate, but was still pretty happy with the 0.002 total I got off of the locker cap. Mind you this was still before placing any shims and w/o the carrier bearing caps installed, so I was even a little surprised that it was as good as that, that it changed in a consistent sweep around the carrier (as opposed to being jittery) and was repeatable.

Again, thanks for coaching me, I just want to be sure that we are diagnosing things properly and not miscommunicating.
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Re: TJ Rubicon Dana 44 Rebuild

Postby Philip » Wed Oct 26, 2016 11:44 am

Check the ring gear mounting surface run out on the carrier without the gear. That tells you if the carrier is machined true. Then check the run out with gear installed. That will tell you if the gear is mounted true. It will also tell if you have a gear machined out of true. I have seen that one time on a new R&P that was not Dana made.

I check for run out on the back side of the ring gear on that flat ledge. You could also remove the markings on one ring gear hold down bolt. Going that way will make sure you use the same point for all checking.

When I remove material from the bottom of hold down caps to tighten crush pressure. I use a set of calipers and a hand file. Your not taking much off. A mill is nice. By the time you would get it setup and done. The hand file would have you into another part of the build.
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Re: TJ Rubicon Dana 44 Rebuild

Postby KCStudly » Wed Oct 26, 2016 1:35 pm

Yeah, I would just hand lap the caps on a surface plate with a sheet of fine emery. Reference to the mill set up was if attempting to do the cap mating surfaces adjacent to the housing saddles around the threaded bolt holes (which is what I thought you had originally suggested); which would also be "above my pay grade". It is my understanding that you need to be careful to keep these mating parts very square and true to one another. It would be very easy to get the surfaces cocked, no longer flat, and/or no longer parallel to one another. I guess you would have to go pretty far to through the bore off to the point that it was no longer round-ish, but that is something to be a little concerned about, too.

Thanks again for the advice. :thumbsup:
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Re: TJ Rubicon Dana 44 Rebuild

Postby KCStudly » Thu Oct 27, 2016 2:50 pm

Last night I took a second, much more critical look at the carrier bearing saddles and caps, and I see no evidence of the bearing cups walking; just slight coloration next to where the race sat that could be attributed to gear oil contamination (staining).

Unhappy with how long the brake cylinder hone was taking, I brought out the big guns… a 1-1/4 diameter x 3/4 x 1/4 shank die grinder stone, sort of like this one:
Image
...using Karl’s electric die grinder like this one:
Image

There was enough of the inner bearing race sticking out below the roller cage to grab in the chuck of the lathe so that I could turn the bearing at a moderately slow speed while grinding, thus maintaining some form of uniformity in the material removal. I would not have attempted this free hand. Anyway, that did the trick and after just a few quick passes the bearing slipped right on to the pinion with no perceptible slop. Now I have an inexpensive inner pinion setup bearing!

Once I cleaned the bearing out with PB Blaster and compressed air (never spin dry a roller bearing; yes it sounds cool but is bad for the bearing) I slipped the old pinion depth shim from the 5.13 gear setup on, and then the bearing. This 4.10 pinion is marked -.5 with the minus sign over the .5 etching. The manual says that gears vary a bit from the planned pinion depth of 2.625 below the axle centerline (or maybe the reference is from the std. pinion depth measuring tool, allowing for the thickness of the mandrel that is used for measuring); so all pinions should be marked with either zero or a +/- offset as to how they best fit with their corresponding ring gear. Plus numbers mean that the pinion meshes with the ring gear best when it is down further in the hole, so less shim; and minus numbers mean that the pinion meshes best when the pinion is closer to the axle centerline, or more shim. Thing is, the examples they give are more like +3 or -1, meaning +.003 and -.001, not -.5; so I am left wondering if my etching actually means -.0005, or half a thou, which seems a little persnickety. By comparing this relative data with the marking on the pinion that was removed, I should be able to make a relative adjustment to the shim and get me somewhere in the ballpark. However, the marking on the 5.13 pinion that came out is something like 4.138 (I can’t recall the exact number at the moment), which as far as I can tell correlates to nothing that I have read.

It gets better. I was happy to find that the 5.13 gear was setup with shims outside of the carrier bearings and under the inner pinion bearing because that means that I only need the one setup bearing. If it had been setup like some are with shims between the carrier bearings and carrier, or between the inner pinion bearing cup and bearing pocket, then I would have to drive stuff in and out more, or would also need setup races that are a slip fit into the housing. So when I decided to see if I could adjust the inner pinion bearing shim I was not happy to see that the setup kit I have only has shims sized for under the inner pinion bearing cup race, and not for the inner pinion cone race. If the 0.060 shim from the 5.13 gear is not correct, I will either have to buy another shim pack, or drive the cup out and use the ones from the kit. I can also sand down the old race turning it into a setup slip fit, but I’d prefer to stick with the inner race shims.

So for now I decided to start with the .060 shim and see where I'm at.

Next up was cleaning more parts. In order to install the outer pinion bearing with any pre-load at all I needed to clean the old pinion yoke, retaining washer and nut. In order to hold the yoke while turning the nut I need to fabricate a holding lever; a special wrench if you will. Now is when I wished that the new pinion yoke had already arrived, but I can still work with the old one for now. I found a suitable piece of heavy angle steel and laid out the U-joint strap bolt pattern with the side of the yoke sitting up against the inside leg of the angle. I was able to punch two of the four holes on the iron worker since Karl already had it setup with the 5/16 inch punch, but the spindle on the punch was too wide to get in close to the vertical leg of the angle, and Karl had active jobs setup in both of the milling machines, so I brought the steel with me to work today and will use the mill here to finish that up as soon as I get done typing this (now off the clock). The new 1330 yoke had arrived last night when I got home, but unfortunately I spaced out and forgot to bring it with me this morning. The plan is to put that pattern on the other end of “the wrench” and the fabricating operations are the same, so I will likely end up doing the same setups twice now. Doh.

Along with that I brought the axles in to use the press to swap the bearings out. I’ll let you all know how things work out next time.
KC
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