Planning rear D44 rebuild and Limited Slip install. Advice?

[J20 project]

Grip lock is just another brand of torsen LS like Truetrac. Mine is 99.9% on road so I don't want a ratcheting locker back there. In the very long future, I plan to put a selectable locker in the front but that will be years from now.

Ayeee...the Grip Pro is like the truetrac...a Torsen gleason variant. While limited slip, no friction discs....

Torsen Torque-Sensing (full name Torsen traction) is a type of limited-slip differential used in automobiles . It was invented by American Vernon Gleasman and manufactured by the Gleason Corporation. Torsen is a portmanteau of Torque-Sensing.

from Wikipedia...


J20

[Dave Jeeper]

I have installed ARB air lockers in a Dana 35 and Dana 30. The Dana 35 is very similar to the Dana 44.


I did not need a case spreader to do mine, but the Dana 44 is heavier duty and it may need one.


I used my harbor freight 20 ton press and a bearing separator (holds the bearing in the press) to remove the old bearings. Old bearings can be ground down to fit loosely on the shafts, and used as setup bearings if needed.


Before disassembly, measure the backlash with your dial indicator. If reusing the same gears, you will be matching the backlash with the new carrier (torsen locker). It will not be necessary to remove the pinion gear if it is in good shape and the seal is good.



It should all go something like this:


Jack up car. Remove diff cover and drain oil. Mount the dial indicator with a magnetic mount to the edge of the diff where the cover was. Position the shaft of the dial indicator at a tangent to the ring gear. Keep the vehicle in park with the e-brake off. Turn the driver's rear tire gently forward and rearward and measure the movement of the ring gear on the dial indicator.


Record the measurements and take photos of the indicator setup so that you can repeat it later. The total movement of the ring gear tooth is the backlash measured in thousands of an inch.


Now, remove the tires, remove the bolts that hold the axle shafts in the axle housing, then remove both axle shafts. Place them aside and keep them clean. Mark the carrier bearing caps so that they can only go back in exactly as they are now. Take photos. Remove the bolts and caps. The carrier may be stuck in the diff housing. Some use a pry bar to loosen the carrier at the bearings, prying it out of the diff housing. You must be careful not to damage the housing, the bearings or the carrier. I tied rope around the two sides of the carrier and used a slide hammer attached to the rope to get the carrier loose. It can pop out while doing this and it is heavy, be careful that it doesn't hit the floor.


Now remove the carrier shims. Keep the driver side shims separate from the passenger shims and label them (baggies work well). On the Dana 44 the shims should be towards the outside of (outboard of) the carrier bearings and the bearings should not need to be removed to take off the shims. The outermost shim on each side is thick and has chamfered edges to ease installation.


Remove the ring gear bolts and ring gear from the old carrier. Install (press) new carrier bearings on the new locker. It is recommended to use new ring gear bolts with loctite on the new carrier and torque to spec.



The carrier needs to be spaced to fit into the case, interface with the ring gear and provide the same backlash as the first carrier. When setting up the new carrier, it may not have exactly the same measurements as the old one, but it should be close. If you just put the same old shims in, the carrier may be too loose or too tight to fit in the space of the diff housing due to slightly different dimensions from the old carrier. Additionally, the carrier may not be in the exact same position left to right. If it is too far right, then the backlash will be decreased, if too far left then increased. First you must adjust the shims to find a fit that allows the carrier to just slip into the housing with no left to right or right to left movement and no gear interference. Install the bearing caps according to the original orientation and install the bolts. Now measure the backlash, it will almost certainly be more or less than the original setting with the original carrier. Move some shims from one side to the other until the backlash is the same as original.


Now you must set the pre-load. The carrier bearings require some side pressure to operate correctly. You must check the spec, it is probably around 10 to 15 thousands. Add 7 thousandths (half of the preload spec) to each side, inboard of the chamfered outside shims. Now you must use a 2x4 and a hammer to drift the carrier into the housing. When you do this it will spread the housing slightly and load the carrier bearings. Install the carrier bearing caps and bolts, then torque. Recheck the backlash. If it is the same as the original measurement, then remove the carrier bolts, install new ones with loctite and torque. If the backlash is not the same, then getting the carrier out now is not going to be easy. It is jammed in there. Hopefully you can reassemble everything now, seal the cover and add fluid. Then test your new setup. Drive it gently at first and do the first fluid change early to check for metal particles (Not good if you find them).



The Dana 35 housings are weaker than the 44 and they stretch during prolonged use. Once they stretch enough the preload is lost and the new carrier can become damaged from operating without preload. I recheck the preload on the Dana 35 every 50,000 miles. I don't know if it needs to be done on a Dana 44 or not.


I am not a pro like some of the other posters on this thread. I did not mean to insult any of them by sharing my experience and I may have made mistakes in what I have described. I hope that others will be kind in their criticism and will focus on helping the original poster of this thread.



Best of luck in doing this job. If you need to remove the pinion gear (for a seal and/or bearing change), then this job will become much more complicated as there is more needed to be done to align the gears correctly.


Dave

[rang-a-stang]

Dah! Yeah, That was a typo/Brain fart (Grip Lok Vs. Grip Pro). Shoulda been Grip Pro all along. I even read several articles on Powertrax website about Grip Pro. I want a LS not a locker. Good catch. Thank you!

Thank you for the really detailed post, Dave Jeeper! Super awesome read!

I am really on the fence about having a shop do this. I have a few emails out to a few shops and will make some calls tomorrow. It's tough because I am 3 hours worth of time zones away from home and by the time I get off work out here, everyone is closed back home.

I feel like my luck says if I do not replace the pinion bearings, they WILL fail and when they do, they will send metal bits into the carrier and take the carrier out with them. That may sound improbable to most but anyone that has read my build thread will understand why it is a concern to me (I have failure after failure after failure). I feel like if I pull the pinion, my lack of experience and bad attention to detail will doom my axle, also.

On the same note, If I take it to a shop, the cost to have this done will take away all the savings I have for tires. My tires are TRASH and MUST be replaced. So if take it to a shop, they fix the diff so I can drive my truck but I can't drive my truck because the tires are toast. Or I do the axle myself, never have any sort of confidence in it, and it pukes on my way to Boise.

No clear answer yet. Still researching.

[Dave Jeeper]

Rang-s-Stang,


You may want to consider a lunch box locker as a temporary solution.


They go inside the carrier where the spider gears are. I have never installed one, but they are much easier than the procedure that I described above for the torsen locker.


Lunch box lockers are cheap, around $250 for the locker and a bit more for some new gear oil and form-a-gasket. I believe that you would not even have to remove the carrier. You remove the diff cover, slide the axle shafts out 6", remove the spider gears and the locker goes inside the carrier. No measurements for backlash, shims, etc.



They are "clicky" style lockers, and are not as strong as a Detroit, but they are easy to install or remove. I would not put one of these in the front, but they are a good option for the rear, if you doubt your skills for the torsen.


Here is a link to instructions with photos:

https://completeoffroad.com/files/spartan_locker_installation_instructions.pdf

If you do take it to a shop, then have them replace all bearings and seals, including the pinion bearings and seals and axle shaft bearings and seals. If you are already paying alot for a job, then have them go the whole 9 yards.



If going bigger than 31" tires and operating at altitude, then re-gearing would be advisable. Then you need to do the front axle also before operating in 4 wheel drive. So this option is big bucks.



I have torsens front and rear on one of my XJ's (small Cherokees) in Colorado. I prefer the ARB air lockers. ARB's are locked when locked and open when not locked. You just flip a switch for the ARB's. The Torsens require light application of the brake while applying gas to engage them in low traction conditions like snow or mud. Once they grab they are great. If you have to keep hitting the brake to re-engage them, it gets old. If I don't use the brake to get them to grab in the loose snow, it seems like they don't engage.


I don't have a ton of experience with them. I swapped in those axles 2 years ago and I usually drive my other XJ's with the ARB's when rock crawling or in deep snow. The one time that I took the torsens rock crawling they did great. Not so much on ice and snow for me in limited trials. The ARB's are much more expensive and more difficult to install, since they require a compressor, wiring and air lines.


Consider the Spartan lunch box locker. I believe that they are called a lunch box because it can be installed in a few hours and they are not very big. Realistically, figure 5 hours to do the Spartan in case things are rusted, stuck, etc. There are other lunch box lockers, I haven't compared them. Best of luck.



Dave

[SJTD]

I think you can set up the pinion depth with the old gears, shims and some math since they are marked but Idunnofosure.

Pretty sure I saw the pinion set up tool set in a Summit or maybe Jegs catalog for a hundred bones or so. I'll have to see if I can dig it up. Again, I'll need it some day even if I'm right since I don't have the old gears for my rear 60...

[rang-a-stang]

I may have found an extremely anti-climatic answer.

Today I was exploring around Oahu (near USCG Air Station Barbers Point) and found an abandoned JK chassis sitting in some brush.


Sure enough, rear axle is still there and sealed up:

The Google Jeep part book says that part number is a Dana 44 with 30 spline axles.


I think I am going to borrow some wrenches from a co-worker that is here local, use the jack from my rental car and pull the spider gears out of this.

Then I can save my money for tires and continue saving up for a Limited slip/rebuild by a shop when I am more ready.

Thoughts? Bad idea? Won't work?

[SJTD]

They going to fit yours? Seems a bit newer.

Maybe would be better to find some feller headed to Hueneme, buy him a few beers and get him to sneak it onto his ship.

Then do another frame swap.

[backroadin']

Were your spider gears bad or is there a limited slip in there?
As to the lunchbox locker - I went down this road and it turns out with the 3.73's I have (d44) the cross shaft will not slide out without removal of the ring gear - which negated the whole simplicity thing with the lunchbox locker since you've got to pull the carrier to remove the ring gear. There's a cutoff - I can't remember which way it goes, but at a certain gear ratio size, the shaft will clear it, and higher or lower it won't. I was told 3.73's would clear it but it does not. So I never installed the locker. Same would be true of swapping spider gears. I seem to remember that higher gear ratios were good to go, but it's been a while.

[RamJetFSJ]

Jk Dana 44 gears are different than old standard 44 gears. Look up the Janet’s engineering Jana K4 kit.

http://www.jantz4x4.com//jantz.php?p=detail&pro=jana_k4

[rang-a-stang]

They going to fit yours? Seems a bit newer.

Maybe would be better to find some feller headed to Hueneme, buy him a few beers and get him to sneak it onto his ship.

Then do another frame swap.

I think the Spider gears and side gears should be the same... if it's an open diff. Anyone know for sure?

Haha! I would consider it (bringing this chassis home)! I am 99% sure this frame is from a stolen Jeep that was stripped and just dumped in this field. It would be hard to get it under my Cherk, legally.

Were your spider gears bad or is there a limited slip in there?
As to the lunchbox locker - I went down this road and it turns out with the 3.73's I have (d44) the cross shaft will not slide out without removal of the ring gear - which negated the whole simplicity thing with the lunchbox locker since you've got to pull the carrier to remove the ring gear. There's a cutoff - I can't remember which way it goes, but at a certain gear ratio size, the shaft will clear it, and higher or lower it won't. I was told 3.73's would clear it but it does not. So I never installed the locker. Same would be true of swapping spider gears. I seem to remember that higher gear ratios were good to go, but it's been a while.

Yeah, busted a spider gear. That's what started this whole thread.


I considered a Lunchbox locker but I don't really "need" a LS or a locker at this point but my long term plan is a LS. I am fairly OK with the gears I have at this point so I do not want to invest in gears or a carrier unless I do the WHOLE axle and then just be done with it. I am just not ready for that yet ($$$$). When I shopped spider gears right after I found my spider gear soup, I found a new set is like $100 and they all seem to be the same for 30 spline axles. I didn't want to spend $100 and end up in the same boat I was before I killed that spider.

Jk Dana 44 gears are different than old standard 44 gears. Look up the Janet’s engineering Jana K4 kit.

http://www.jantz4x4.com//jantz.php?p=detail&pro=jana_k4

Copy that. I am only going to grab the spider gears, side gears, and pin. I don't plan to grab the whole carrier. I have to get these home in my suitcase.
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Today I picked up a metric ratcheting wrench set (8-19mm), a hammer, and a big screw to use as a drift. There is a chain there at the sight I am going to use to pull the axles out of the housing, too. My rental car does not have a jack (annoyed) but there is also an abandoned Saturn around the corner from the JK Frame and I am hoping there is still a jack in it's trunk.

[rang-a-stang]

Got the cover off and the inside looks great! Fresh oil in it.

As a wise man once said:

...the cross shaft will not slide out without removal of the ring gear...

So I started pulling it apart to get the carrier out. I was able to disassemble everything but will need a slide hammer from McParts tool loaner pool. Also, on one of the axle retaining plates, the stud is spinning with the nut. Not sure how I will get that off with the limited tools I have. If I was home, I would grab a grinder and cut it off but working out of a hotel room. I'll figure something out.

[Dave Jeeper]

Cold chisel and small sledge hammer?

[J20 project]

Damn, National drivetrain lists a spider gear set for $50

[J20 project]

Also, they list a different spider gear kit number for a jk.

[rang-a-stang]

Cold chisel and small sledge hammer?

That's what I was thinking, too. More below.

Damn, National drivetrain lists a spider gear set for $50

Also, they list a different spider gear kit number for a jk.

That's alot less than I have been seeing! When I was looking, I was seeing $75+. Stupid.

Whelp, I guess it's better that I couldn't get them out. More below.
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Got bored in my hotel room so I went back out. Picked up a slide hammer from McParts and a cold chisel from Home Depot.
1) Started with the slide hammer on the axle where I did get all 4 nuts off the retaining plate. I beat the living H E double hockey sticks out of that thing and it laughed at me! In fact, the 3 grade 5 nuts I used to connect the axle pulling flange to the lug studs all had damage to them. I spent a good 30 mins slamming that slide hammer and got frustrated, blistery hands, and sweaty.
2) I thought, Maybe if I over-torque'ed the nut, I could bust the stud off. I used my wrench and a pipe about 2 feet long and started cranking away. It started off well. I went slow and I was able to pull about 2 threads through the nut, then the nut just started spinning on the stud (though the stud was holding). I spun it a few more times but it became clear that the nut was just spinning on stripped threads.
3) Then I tried my cold chisel and hammer. I banged away on both the nut and the stud and I just wasn't making much progress. So between the slow progress with the cold chisel and me not being able to pull the other side's axle off, I gave up.

I called a bust. I have invested about $15 in tools (after I return the wrench set I bought and the loaner tools from McParts) and hardware and about 4 hours of wrenching. I am OK with that because it was pretty fun wrenching on it and it killed a boring day in my hotel.

SOOOOoooo.... Would the spider gears in my front axle be the same as the ones I need for my back axle? Maybe I will just pilfer my front axle so I can at least drive my truck for now (eerr... "now" meaning, next month). Then, I will continue to save up for my LS. Then when I have $$ for my LS in the back, I'll move the spider gears back to the front.