Re: oil leak
If the bellows has oil in it, then it can only come from one place, the front seal. And most likely the seal surface on the yoke is grooved.
You have 3 choices.
1. Replace the yoke.
2. 'Speedi-sleeve' the yoke.
3. Set the seal 0.020" deeper and have it run on a 'new' surface..
You'll need to replace the seal regardless, so to do that you'll need the special tool to remove the retainer ring on the front of the 'top box' (upper half of the complete drive). Once the retainer is off, then pull the drive gear out. Set it up in a vice and remove the nut on the end of the yoke. Disassemble the drive gear and bearings off the yoke. replace the old seal (0.020" deeper if that's the method you choose) and reassemble the yoke, set the bearing preload as per spec...
Reassembly of the rest of the system is reverse of disassembly....
Good luck.... and don't forget to pressure AND vacuum test the drive when you're done.
Chris...........