98 XJ, 4WD stock 35 Diff, stock 231 transfer case, 108K miles.

A PO drove this XJ on salted winter roads in Mass., and it now has seriously rusted drive shaft, rear yoke, yoke nut, straps and strap bolts. The rear yoke and shaft are rusted so badly I think at some point it's gonna break. I'd rather replace it all (rear drive shaft, u-joints, rear diff yoke, yoke nut, straps and strap bolts) and not have to worry about getting stranded.

Recently I replaced the badly rusted and flattened rear springs and restored (scraped, wire brushed, Ospho'd, primed... with zinc chromate aircraft primer... and painted black) the rear rear axle and anti-sway bar. Now I want to replace the rear drive shaft, u-joints, straps and strap bolts, diff yoke and yoke nut.

Newbie to this site, but have searched this and other sites for drive shaft replacement info. Still have some questions and still looking for a good writeup on replacing the rear diff yoke and nut.

1. See photo. This is the replacement shaft from a '99. This main shaft is 29" from end to end as badly depicted by the blue line in the photo. The same measurement on the shaft that is now on my XJ is 30". Measured twice on both. Question: should I abandon this new shaft and go for one of the same length OR will the ability of the transfer case yoke/shaft to slide in and out take up the one inch difference so that I can use this 1" shorter drive shaft?

2. I really need to replace the yoke and yoke nut on the diff. I have read about marking the the yoke and nut so that it goes back exactly the same way for balance. Seems to me that with a new drive shaft and new yoke, that whole process is not necessary because the new shaft and yoke will have a new and unknown balance point. So I believe the right procedure is to put it on, try it, and if I get a bad vibration, disco the shaft and begin rotating it 45 degrees until I can find a sweet spot where it will not vibrate. Yes? No? Thoughts and opinions?

3. While I have the diff yoke and nut off, should I go ahead and replace the seal? Right now it does not leak. Got the new seal.

4. When I replace the yoke and nut with new ones do I need to replace the crush sleeve? Got a new crush sleeve should I need it.

5. I have the '98 factory service manual. It calls of all kinds of special tools to replace the yoke and nut. Final question is, can a reasonably adept amateur mechanic like me do this or should I just take it to a drive line shop? What are the downsides? Do I run a big risk of screwing up the internal alignment and tolerances of the diff?

Thanks in advance for the advice and any references to links.

 

the 29" d-shaft will work fine..... if your jeep is lifted then you may want to look more into drop and the d-shaft movement, just make sure the yoke stays on the t-case o-put shaft with a decent enough depth....
also the rear yoke is a real no biggie..... if you have the spare parts, you may as well replace them, the seal and crush sleeve, as for making sure the yoke is on correctly again, i'm pretty sure they have a gap grove in the spline so you cannot put them back on incorrectly but i may be wrong, and if so then just try your 45 degree turn idea.
and no you do not need a prof. shop to remove the yoke/nut, just grab an inpact gun and the correct socket and remove, then re-install and give it a go