8.25 8 1/4 Rebuild and modification

- new bearing kit. for the two carrier bearings and two pinion bearings. i didnt get new axle bearings because they were already brand new. it should also come with new ring gear bolts and some lock-tite and new races for your carrier and pinion bearings along with new washers and new pinion bolt.

-start by removing the differential cover and draining the oil.

-take off your wheels and drum brake shoes.

which required an air wrench and it clamps down underneath the bearings and as you tighten down the bolt, it pulls off the bearings.

the only reason you remove the old bearing from the old pinion is to have this shim, without it your new pinion will not set right with the new bearing.

- nextly you can put your new bearings on, i started with the inside pinion bearing. it would be wise to use a hydraulic press. sit your old race on top of the bearing the way it would sit in the differential so you dont damage the bearing as you press down on it.

make sure the shim is in between the bearing and pinion and most importantly while your pressing the bearing in , make sure you are pressing it evenly because if one side of the bearing starts going on faster, it could cause you a great headache when you ruin your new bearing.

-then the carrier bearings, sit the bearings on as they would sit (smaller side of the bearing facing outward, then sit the old races in place on the bearings. i pressed them both in at the same time like this

-start by holding the ring gear in place and starting a few of the reverse threaded bolts so they will pull it into place. pull the bolts back out and put them in one at a time after dabbing some loc-tite on them. they are very important bolts and are almost impossible to find. so be careful as you torque them down. i used a very small impact wrench and put it on the lowest setting.

-again since i had the jeep on the lift i decided now would be the time to drain the front differential which has never had its oil changed (my jeep has 110 k on it) so it was overdue. i also decided now would be the perfect time to get synthetic gear oil for my differentials. i chose mobil 1 synthetic 75w-90 gear oil

-i used a air tool with a wire wheel attachment to get rid of the gasket covering the rim of the differential and cover. the same was done to the 8.25 cover and differential. if you dont have an air tool like that a scraper putty knife or wire brush works fine as well.

-put new gasket on the diff cover and and bolt it back up and fill 'er up with some good synthetic.

-now comes the hard part of setting the new pinion and spider gears/carrier

pinion depth- pinion depth is the depth of the pinion in relation to the axle centerline, and is adjusted by adding or subtracting shims to move your pinion in or out. pinion depth is verified by tooth contact pattern. your ideal pattern is centered between the face and flank. pinion depth must be set properly to avoid unneccessary noise and even worse, gear failure