Figured I'd post some tips for future newbs. If you've done it, I seriously doubt you'll learn anything new.

1. I had an aftermarket front shaft with the larger u-joints. The Neapco parts numbers were 1-0154 for the joints and 7-0081 for the centering ball (mine was greaseable). I got the joints locally but had to order the ball from ebay. It came in a Neapco box and looked totally legit. My centering ball came out very easily with a slide hammer. Be sure to inspect your joints - one of mine had an extra pin laying in the cap, so I couldn't push the cap all the way onto the joint. I had to pull the cap back out of the shaft to figure out why it wouldn't seat all the way.

1a. The front shaft was stuck in the transfer case. It has a lip that protrudes into the case about 3/16", and it was pretty damn stuck. I had a tap it with a small sledge on the double cardan joint away from the transfer case to work it loose.

2. Buy some ratcheting wrenches if you don't already own them. They'll speed things up a bit.

3. Be careful not to strip the nuts - they're pretty soft. I replaced all mine with Grade 8, to include the front bolts.

4. A trick I used on the rear shaft's 9/16" front nuts was to break them loose with a wrench, then use an over sized socket (15mm) to take them off. Sped things up a lot.

5. The Neapco joints for the front shaft came with the inverted flush grease fittings, the one for the back shaft came with a normal grease fitting, and the centering ball came with no fitting. I couldn't find a flush nozzle for my greasegun anywhere. A few places sell a rubber tipped nozzle that looks like it'll work, but didn't. Finally at Autozone I found a long metal needle tip (about 4 inches long and 0.25 inches in diameter) that worked.

6. If you put the transfer shifter in N, you can lift one front or one rear tire and spin the drive shafts easily to make them easier to work on. Then lower it back down for the actual wrenching.

7. I would definitely get u-joints with the grease fittings on the caps. Part of the reason I replaced my old joints is it was almost impossible to grease them with the fittings down in the double cardan.

8. Disassembling/reassembling the double cardan is interesting. Start from the outside and work in. First yolk, then DC, then 2nd u-joint. When you reaseemble, work in the opposite direction. When you get the where you are putting the piece with the centering ball back in, it requires some manipulation to get everything to line up, and then you have to keep pressure on it as you put the caps on the joint. It might be easier with two sets of hands.

If I can think of anything else, I'll add it. One thing I'll add - the cheapest place I've found to buy aftermarket parts is ebay, so I'd at least check it when you're parts shopping.

 

BTW, there were two big reasons I decided to rebuild a aftermarket shaft - I was uncertain about how often they had been greased, and the design made them very difficult to for me to grease properly.

I'm glad I did it. When I got those joints out, the grease was black inside them. I'm not sure they'd ever been properly greased.

I am going to put a sheet of paper in the front of the truck's manual to log the work I do. This way a future owner will have some idea when the fluids have been changed and how the drive shafts have been cared for. I also plan to list the parts I used so he isn't hunting for them. I've never been this **** about record keeping, but I feel like the mods to this truck will make it painful to own unless I give them a thorough list of what I've done.

 

Quite a detailed and impressive write-up.
Not sure I will tackle this myself.

How does this shaft perform on the highway?
Do you think balancing the shaft will be an issue?

 

I haven't test driven it yet. I installed the shafts today, and planned to replace the crank sensor but it started pouring rain. So I hope to get it on the road tomorrow.

I'm curious about the balance myself. The truck had a bit of a vibration (felt in the seat) around 60, but I think that's tires. I'll let you know. If you mark everything before you pull it apart, balance should not bean issue.

I've done u-joints on 3-4 vehicles now. It's not bad. I definitely recommend using a vice or c-clamp to press the joints in and out. I seem to recall that the first joints I did (about 15 years ago), I hammered them out of the shaft, and that sucked. Then the second set of joints had been in the car 25 years, so that was a huge pain. So, actually the Disco wasn't bad in the scheme of things.

 

The easist for me was using two sockets; one to fit on the inside to press the cap and one on the opposing side that was large and deep enough to sit on the yoke. Definitely would second the advice for using a vise; hammering is okay, but it can be a pain and you could ding your yoke/driveshaft if your blow is off-center. Only good for trail repair, IMHO.