Rear differential input seal replacement on 93 t800

First question - Do you have the proper tools? I did my own and had to borrow tools to do it, iirc it's at least a 3/4 drive, 2 5/16 socket (depending on your rear ends).
Unless you want the satisfaction of "doing it yourself", you're time and money ahead by paying a shop.

 

3/4 inch impact . A good one.
Or 1" impact is better.

Big socket selection 2" and up.

Sometimes those yolks can be a bugger to get off the input shaft if it has been on there long time. You might need a puller if you can't beat it off with a hammer.

Other then that perty straight forward.

I ussally replace the yolk , nut and U joint with new if it' been on there long time. Seal surface will have big groove in it.

 

I'd get a spare u-joint too. I've had a few where the caps are seized in and it needs to be torched out. Had others that had the trunnion blow clean through the end of the cap. May even get it out and find the u-joint is worn out or the needles have brinelled (beaten in) the trunnion ends.

 

Sure. Always check the axle vent to be clear or replace it whenever replacing a differential seal. If it is plugged you'll be replacing it again in short order. Inspect the yoke carefully for a seal groove worn in and replace if worn. I like to install a new yoke nut, or at least red loctite the old one upon install.

 

All of the previous are good points but I will add a couple.
1: If the yoke has side play tighten the nut first and see if it tightens up. If it does not shims need to be removed.
2: Get that outer bearing out and look at all you can see for condition.
3: There are dial indicator measurements and such but a field fix is chuck a thin shim and put the yoke on with the old nut. If it still has slack remove a bit more. When the slack is gone put the new seal in and install yoke with new nut. They are considered a one use item.
4: Wear rings ( speedy sleeves ) are also available. They do a good job of repairing damaged yokes if properly installed. Some of them require a different seal.