Colby's Front 488 gear install
(22 low res pics loading)
May 11 2004

Colby had attempted the install and was having some issues so he boxed up both diffs and sent them to me. The box broke open in one of the corners and some stuff was lost. Carrier bearing cups,pinion washer, and a pair of bolts went bye-bye. No biggie as I had some back-ups. These are 4.88 US GEAR brand and properly installed will last longer than the rest of the truck. Being that these are going in the front, a crush sleeve is ok to use.

First, I have to remove the pinion and try a starter shim.....I tried the brass punch but it was too solid in there so.....

I eased it out with the 10 ton press. This press has seen so much's paid for itself 10 times over.

These bearings go in the garbage as they are no good without cups......A good used set shall suffice.

The used ones are Timken.

I roughed up the surfaces, cleaned them with starting fluid, and applied some of this stuff. It's like a "loc-tite" but designed for non-threaded surfaces.....prevents spun bearing damage.

I also removed the ring gear and filed the surface smooth to minimize run-out.

Loc-tite is the way to go.

Cross-tightened them to 70 ft/lbs.

Back to the pinion....I chose to use a .098" shim for starters. These micrometers offer some real precision....I have a cheapie set of 14 dollar calipers that I like to use also.

The press easily lands the bearing down onto the shim.

The races were already installed...but just for grins, I used a soft punch to make sure they were seated ....... and I found they were not. I bet that was causing you some grief, Colby ;)
edit---Best to stay away from all punches...use an old race to evenly "pat" the new race down. 1-7-2011 ZUK

I skipped ahead a bit here but basically re-installed the pinion without the crush-sleeve but tightened the nut just enough to offer some pre-load then installed the carrier with about .008 backlash. I painted the teeth and placed some drag on the ring-gear while turning the pinion. This gives a good paint. This is the drive side and is too shallow with .098. I don't care so much about where the pattern is from top to bottom as oriented in the above pic.....I care alot about the "left to right" how deep it is. The "up-down" location of the pattern is influenced via backlash but that influence is very limited.

I got a little carried away and made a big change in shim here.....I re-shimmed to .108" (a 10 thou increase) and now it is too the right mesh is somewhere between 098 and 108.

Re-shimmed to .103 and this is more like it. This is the drive side and using the normal .008 backlash. I have very little influence trying to push that pattern "up" closer to center....actually, under torque the pattern dynamically moves in that direction. It moves toward the center which is a good place to be under conditions of high torque. Now since this is the front ring/pinion, the only time this side sees contact is with tranny in reverse, for what it's worth.

This is the coast side....this is the side contacted while going forward. Good pattern.

So now that I have the right pinion shim, now I get to take it down again to install the crush sleeve......sure is nice having the electric impact....for everything I do in my little shop.

Now it's just a matter of dropping the new crush in there...then the bearing, seal, yoke, and nut in that order.

I used Ultra-Blue RTV on the metal seal lip and some good grease on the rubber seal to prevent a dry start. Using a 600 grade fine sand-paper, I wet-sanded the yoke surface to get the best possible seal.

It only took 1 arm to crush the sleeve down....

After all the slack was out of the yoke, I very carefully continued to crush the sleeve until I reached about 15 in/lbs on the pinion pre-load measurement. I also used the blue Loc-Tite on the main pinion nut and staked it as well....that ain't ever gonna loosen on it's own!

I then re-installed the carrier and made sure carrier bearings were very TIGHT and maintained the .008 back-lash. How many diffs have exploded because the carrier bearings were only snugged finger tight I am not certain. One diff ready to head back to Bountiful, Utah. I will also box it....and I will make it UPS proof ;)