7.25 pinion seal replacement questions can't get the pinion nut off

Lasalle said
How do you hold the yoke still to remove the nut without the tool in the service manual?

large pipe wrench works.

Lasalle said
When I reinstall the yoke on the pinion shaft, does it push right on or do I need a tool or some method to push it back on ?

You may have to tap it with a hammer to "remove" it. Same when putting it on after aligning the splines.
After removing the nut and washer spray it with penetrating oil to loosen the splines.

Lasalle said
3. Does the yoke need to go back on the shaft in the same position?

Not really but it can't hurt.

Lasalle said
According to the FSM this differential has a crush sleeve. Advice on getting the nut back on properly? A previous thread on this forum suggested marking the nut and the shaft and counting the number of turns to remove and using the same number of turns to tighten. Does this work?

Yes. Also use red Loctite on the threads. I usually go about 1/8 to 1/4 turn more.

Lasalle said
Is it better to replace the crush sleeve? Is that more involved and harder?

That involves complete dis-assembly . You will be fine with above.