I'm going to install my new Eaton posi this weekend. Just the posi unit, I'm not going to do gears, my 3.73's are staying. My question is....is there a breakin time for the posi unit? I know there's a procedure for new gears, but is there any for just a new Eaton posi unit? I'd like to run it at a test n tune Tues. night, if possible.

 

As a matter of fact I just put the eaton 400# unit in my truck last night and it only cost me a case of beer for the install. I dont think there is a break in period for them. I gave it hell all last night offroad and onroad. I would say drive it like you stole it. Offroad the locker is alright but when one wheel spins you have to gas it to get the other one to lock in but once it does its like a full on locker.

 

If the bearings are going to be new on the case you should get one heat cycle in them. That should do it. New bearings generate a lot of heat initially, but the diff bearings only turn 1/4 the speed of the pinion bearings so they arent as bad.

 

Yeah....I just got back from having new bearings pressed on. I have the install kit, with new ring gear bolts, gaskets,shims, and one pint of GM additive, regular 80/90 lube. We have dial indicators, jack, stands, and all that. Can you think of any other things I might need?

 

A base for the dial indicator, torque wrench, I think thats it.

BTW- make sure you take a backlash reading before removing the old stuff, then try to get the new stuff the same to avoid any noise. Also, the case should have to be tapped into the housing so it can preload the bearings.

 

Thanks. I appreciate the help!

 

I broke mine in about 400 miles
and changed the fluid before I started beating on it

even though it was the same gears
I feel like the contact patch between the ring and pinion
will still be a little different
even if its off just a few thousandths
might be all it takes to tear something up

It may be overkill but worth that little extra attention IMO

 

I just swapped out the G80 in my truck to an Eaton unit and it was a slam dunk. The thick washer-like shim that was in the rear from the factory on each side of the carrier fit when I reinstalled and the backlash was the same. This may have been luck but no undue stress to do this swap in my truck. Of course I had new shims ready if something needed to be adjusted but I was amazed that no adjustments were needed. No noise or issues after about 500 miles....only two black stripes.

 

I used the same washers from mine to. I thought it was kind of weird but I had .006 coming out ano .006 going in.

 

same but .0055 here before and after
I was also impressed that it fit so well

wish my luck went this well with everything