I still have some questions, even after reading past threads and watching videos. This thread, https://www.cherokeeforum.com/f67/ea...nstall-245847/ , was helpful.

I'm installing a truetrac LSD in my 8.25 Chrylser 29-spline differential.

It looks like I should be replacing pinion and carrier bearings, and axle seals while I'm at it.

I have torque wrenches and am buying a dial indicator with magnetic base.

Do I need a special tool to adjust backlash?

Do I need to have a pack of shims on hand.

Would something like this 'basic' rebuild kit have everything I need? If not, what is it missing?
https://www.rockauto.com/en/moreinfo...=2224&jsn=2101

I already have the truetrac, so I've kinda put myself into a corner on figuring this out. I've had it for a while and I'm assuming I read someplace that it's 'not to difficult' or something similar, because I don't recall having any questions at the time of purchase. Opps.

Any videos or writeups you know that might be helpful? Even something showing the same job on a similar differential might help. I just don't know what, if any, differentials might be similar. Most videos seem to be of a truetrac in a dana 35 or a lunchbox type locker in an 8.25. I'm not sure what the differences are in either case, but I'll continue to research.

When I did the differential service a few years back I installed a lubelocker gasket. I know it's trivial, but I'm kinda excited that I might actually benefit from it on this job - that is, not having to scrap off rtv and paper gasket bits.

Special tools needed
- Magnetic mounted dial indicator (measure backlash with this before tearing anything apart so that you can match it back up going together).
- Back lash adjusting tool. This slides in through where the axles go. I made my own with a long pipe and nut but can be purchased if needed.
- TQ wrench

Parts to buy
- Carrier bearings. Not needed but easier if you dont have the right tools to get the old ones off. Bake these in the oven at 200° for 30 min and they should slide right on the carrier.
- Ring gear bolts. Dont remember how many.
- Not a bad idea to get axle seals since you are already in there and you could damage them getting the axles out.

Stuff you dont need
- Anything for the pinion as you will not be touching that.

Thanks!

Looks like 10 ring gear bolts in a dana 35. FSM shows one bolt, but there are definitely 10 holes... and turns out they are sold in a pack of 10.

Anything I need to do with shims? Sounds like they might not be needed for what I'm doing.

Shims are only for the pinion which you wont be touching. The 8.25 has built in adjusters which take place of the carrier shims in order to set back lash. Again, you will need the special tool for the adjustment. This should end up being a super easy job for you. The hardest part is getting the bearings on the carrier before they cool down.

You need to make a tool for the side adjusters, and if the pinion bearings are in good shape I wouldn't touch them. Just measure the backlash before you take the old carrier out. Install the ring gear and new carrier bearings and races on the Truetrac, then install it and set the backlash to what it was before.

Also remember the ring gear bolts on a Chrysler 8.25 are left hand thread.

Any help figuring out backlash is appreciated.
Axle shafts are out. I’m attempting to measure backlash, but I can’t identify any play between the pinion and ring gears.

Next I’ll try cleaning out the diff. Maybe there is lube gunk taking up any play?

Otherwise I’m at a loss. I’ve tried with driveshaft connected and also disconnected at the rear u-bolt (double cardan style d.s.).

Does the long hex-drive tool that goes in the axle shaft have anything to so with backlash?

Thanks for anyone that can comment. I’m smart about some things, maybe, but not this one.

I found this in response to a similar question, so I'm digging in to see if it clarifies things.

The FSM clears a lot of things up. Reading that and following a video example of someone setting backlash during a rebuild according to FSM procedures gives me some confidence.

Ahh... removed side gears and differential pinions from the differential case... backlash is very clear now.

I don't feel quite like Neo when he learned kung-fu, but things are looking up!

Edit... yeah, I was off a bit here.

I assume this is because I removed the adjuster locks and probably messed up adjusters, though I’m interested in knowing if this could be a sign of something more.

I failed to mark which pinion and ring gear teeth go together, but otherwise I am feeling like I can get this all back together and within spec. It may not make it another 200k miles, but I at least won’t be afraid of it.

Edit... this was a dumb statement. This all made more sense after some sleep and another read of the FSM.

I got myself learned on backlash now. I finally got a backlash read of around 0.007" and decided to check the gear pattern.

But, I was an idiot when I disassembled the thing, so I didn't get a coherent initial backlash reading.

To me, the drive side looks good, but appears a little deep. The coast side however isn't centered. I didn't touch the pinion and as far as I know, it's original. I've had it since 2010 and taken it from 102k to 199k.

I'd like to avoid replacing the pinion gear... it did not appear to be a good time when I reviewed the procedure, but I'll do what's necessary to finish the job right. I do have new carrier bearings and cups installed.

Any advice is appreciated.


drive

coast

I cant realy see your pattern

I used 2 side adjusters one in each axle tube when i set backlash on mine.

I would rather run shims than side adjusters much easier for me. I appear to be alone on this because everyone says the 8.25 side adjusters are easier than shims.

I despise it so much i was given the opportunity to do it twice. Turned my first 4.88 gear set into a molten chunk of metal.

Though the 8.25 isnt a axle i like to work on i did learn alot and even after by 2 gear sets saved tons of labor expenses and time over a shop doing the work.

Dont befraid to tesr it apart and check recheck

I wouldn't call what I went through with it easy, but after two days of trying it sorta clicked after a while.

I don't have proper marking paint, but the anti-seize compound works pretty well. The wear area looks a lot like a shadow in the photo.

I'll order some gear marking compound... this thing won't be going back together until I get a set of ironman4x4fab no-lift shackle brackets. ETA is unknown on those.