When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
At this point, it is time to tear everything apart and install the new pinion seal & outer pinion bearing, new outer inner bearing, crush sleeve, yoke, and pinion nut.
1. Prelube the outer pinion bearing with gear oil.
2. Place the outer pinion bearing into the housing.
3. Rub grease or vaseline all over the garter spring on the pinion seal to keep the spring in place during installation.
4. Install the pinion seal using a race driver kit and hammer or a block of wood and a hammer.
5. Prelube the pinion seal and seal surface of the pinion yoke with gear oil.
6. Press the inner bearing onto the pinion using a shop press or a hammer and piece of pipe.
7. Install the crush sleeve onto the pinion.
8. Slide the pinion yoke into the pinion seal and press the yoke towards the inside of the housing so that the outer pinion bearing is seated into its race. Hold the yoke here.
9. With your other hand, slide the pinion into the housing until it partially engages the yoke. You will not be able to force the pinion passed this point due to the press fit between the outer pinion bearing and the pinion.
10. Thread the OLD pinion nut onto the pinion and tighten it a few turns.
11. Remove the pinion nut, install the pinion nut washer and reinstall the OLD pinion nut. Do not tighten the nut yet.
Now we are going to set the pinion bearing preload using the inch pound torque wrench.
1. Tighten the OLD pinion nut a little at a time while checking the play. This will take considerable effort as you will have to crush the crush sleeve. You will need an impact wrench, or 3/4" rachet & pipe wrench with cheater pipes. Once there is no more play, or once the pinion no longer moves in and out of the housing, the pinion bearings are seated in their races.
2. Remove the OLD pinion nut.
3. Use a liberal amount of thread locker on the NEW pinion nut and install it on the pinion.
4. Either use short controlled blasts with impact wrench or turn the pinion nut a small amount using the rachet/pipe wrench combo.
5. After each incremental tightening, give the pinion a few spins back and forth or else the initial torque wrench readings will be higher than what it really is.
6. Check the pinion bearing preload using the inch pound bar type torque wrench after each short blast with the impact wrench or small turn with the rachet and pipe wrench.
7. One you achieve 14-19 inch pounds of preload (drag) you are done.
If you get too much preload (over crush the sleeve) you will need to take everything apart, install a new crush sleeve, and start over. Be careful.
After you have achieved the proper pinion bearing preload, it is now time to reassemble the axle.
I do it in this order:
1. Re-install differential and torque carrier bearing cap bolts to 60 ft. lbs. Be sure to use thread locker.
2. Slide the axle shafts in and install the c-clips.
3. Install differential crosspin and lock bolt.
4. Clean the differential cover, and the differential cover gasket mating surfaces.
5. Install the differential cover with the new gasket.
6. Install the brakes.
7. Install the wheels.
8. Lower the truck.
9. Access the fill plug on the passenger side of the axle near the pinion and fill with 3 QTs of 80W-90 Name Brand gear oil.
10. Break in gears.
1. NO hard acceleration.
2. NO heavy hauling.
3. NO heavy towing.
4. NO driving over 60 mph.
Once the gears are installed, drive the vehicle for about 30 minutes while keeping the "NO" list above in mind. After 30 minutes, park and let the differential cool completely. This initial break-in is very important. After the differential is cooled continue the break-in with the "NO" list in mind for 500 miles. After 500 miles, change the gear oil and have fun.
USED GEARS
Used gears do not require any break-in. If you knew what the original pinion depth and backlash was for said used gear set, try and duplicate those settings. If not, follow the specs written out in the Yukon Install Manual.
OEM/AAM GEARS
These gears are a little more difficult to install as they require a tighter backlash than other gears. The required backlash is 3-6 thousanths.
Awesome write up Axis, thanks a lot I've heard nothing but good things about your abilities, it appears that you are the man when it comes to setting up gears, keep up the good work
04-03-2010, 06:57 PM
I've heard nothing but good things about your abilities, it appears that you are the man when it comes to setting up gears, keep up the good work 
