H3 Front Differential Pinion bearing preload lost. How to get preload?

[Guerrero]

Well, I am back,

I came back to desert sahara in morocco in April, and the H3 was a beast, dunes, running, jumping...everything. But before the trip, and since 2 or 3 years ago, I was listening the typical noise of front differential pinion bearing under coast, due to lost of pinion bearing preload. After the desert trip, now is more noticeable and i decided that is the moment to adjust it.

So...I know by far the procedure, adjusting it by small increments of 1/8 inch, and test it, until the pinion bearing noise is dissapear or very low noticeable. That is correct?
Another suggestion doing this? (4speedfunk jaja). A mechanic told me that adjusting this preload you make the fitment between the pinion and rim woud be far than before...is true? I thought that this small increment would be minimal in deep.

Thanks you so much, great forum and great Hummer product. Here in Europe, in Spain, there are a lot of Hummer Haters. They suggest that toyota, nissan, or mitsubishi is by far better.
I am very proud that since they meet me, they dont say the same about this brand!

Thanks again. Guerrero

 

[Bruces]

I thought the pinion preload was measured by drag when torquing the crush sleeve. If you lost the right amount you pull pinion, replace crush sleeve and retorque. Measure often before final seal and nut install.

 

[4speedfunk]

Preload adjustment will not effect pinion depth. The two are different and can be adjusted via two different things.
On the AAM-7.6, pinion depth is adjusted via a shim under the inner pinion bearing. Preload is set via the crush sleeve. You can do a quicky fix by over-crushing the existing crush sleeve. This can work but, it often only prolongs the inevitable (replacing the pinion bearings and races).
If all you are doing is replacing the bearings, you can leave the depth shim alone, and reuse it.


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[Guerrero]

Thanks for the answer!

I will try to over-crush the existing crush sleeve for now. I think that over torque the nut with small increments of 1/8 inch, and test it until the noise is gone is the right procedure to do it, am I wrong?

 

[4speedfunk]

Before you do anything...take the driveshaft off and swing it out of the way. Grab the yoke and see if you can feel any "shake". It's sometimes hard to tell the difference between lash and preload. You should feel some lash (back & forth rotation)...but not any "shake" (up-down or side to side). If it's really bad it will visibly "wobble", and the seal is probably leaking. Let's assume this is not the case.
I use a big 36" pipe wrench on the yoke, and a 24" breaker bar with a 36" cheater pipe on the handle. I usually jamb the wrench up against the shop floor and crank on the breaker to rotate. Do exactly like you said...go slow...check often. It's a one pass deal...you can't go back if you get it too tight. Remember...you're only trying to get the rattle out of it. It should not be tight.


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