xjnm

Since I could never find a good writeup on this, here is mine:
Your slip yoke allows the driveshaft to move in and out as your suspension compresses. If it is dry, it will shudder on acceleration and braking. This is for a 4x4, I make no guarantees if it is the same for a 2x4, but it probably is similar, just no transfer case.

Tools:
8mm ratchet with long extension or 8 mm wrench
hammer
grease of your choice (I used lucas red n' tacky)
small flathead
small pliers
new hose clamps, zip ties, or OEM rubber boot clamps

1) PUT YOUR PARKING BRAKE ON! And also put something in front/behind the wheels, like a log. Park will not hold your jeep once your driveshaft is off.
Remove the clips holding on the rubber boot at your transfer case. These require the screwdriver and pliers. If you are careful, you may be able to re-use them. Take off the straps holding your U joint to the rear axle with the 8mm ratchet and extension. If you cant reach all of them, get out from under the jeep and roll it forward a little bit.

2) At this point your driveshaft should slide back off the yoke at the transmission/ transfer case and fall off in your hands. If it is stuck, take your hammer and tap on the u joints until the rust breaks free. Don't tap on the driveshaft because you risk unbalancing it.
It should then look something like this: If you have 2wd, this may look different. This is also a good time to check your U joints.

3) Slide off the rubber boot (if you have one), and take a rag and a solvent of your choice and clean off the splines on the output shaft and the splines on the inside of the driveshaft. Inspect both sets of splines for any damage. Don't worry about marking where the splines met up, the driveshaft is not balanced in relation to the output spline. Also clean the old grease out of the inside of the rubber boot.


4) Next, take your grease ( I used Lucas red n' tacky with antiseize, $6 for the tube at AZ, but any grease probably works), and put a little bit inside the boot, and a generous amount on the output shaft and the splines on the inside of the driveshaft. Make sure that the grease is all worked in to the splines.


5) Slide the rubber boot back on.
6)For this step, it may help to have your transfer case in neutral. But put something in front and behind the tires so it doesn't start rolling. Slide the driveshaft back on to the output spline. The grease may put up some resistance, but thats ok. If it is too much to get the U joint back into place, just take some out. Since the t case is in N, you can spin the driveshaft and output shaft to match up the u joints to the yoke at your axle.
7) Once you have it in the yoke, reinstall the bolts and straps. Don't strip the bolt trying to tighten them, it only gets so tight, and many people put blue locktite on them as well.
8)Then, to secure the rubber boot, you have to either
a) try to reuse the factory clamp things
b) use zip ties or hose clamps


I couldn't reuse the factory clamps, they were slipping around too much. I may end up going to autozone and trying to find a better replacement than zip ties, but many people say those work fine. I used 2 zip ties on the t case end and a hose clamp on the other end, but make sure you cut the ends short because remember, this thing is spinning crazy fast down the highway. Check to see if dangling ends will smack anything when it spins.

After this, you are done! Give it a test drive and see how it feels.

If anyone has any useful tips, please put them in the comments! This thread is meant for people who are searching this on google and can't find anything.
Happy driving
xjnm

PatHenry

Nice write up!

I would add - be careful not to knock the loose u-joint caps (the ones under the straps on the axle side) off since the needle bearings can be lost and then you're replacing the joint.

Also, if your u-joints are greasable, they are a lot easier to grease with the shaft out. Put a c-clamp on the loose caps and grease them until grease comes out of the caps.

investinwaffles

I use Lucas Green grease, very water resistant to resist wash out. It's uses a polyurea thickener, so it doesn't play well with other greases. Has worked great for years in everything from u joints to high speed bearings

Been thinking of switching to the AMSOIL NGLI #2 Truck grease when I run out though. Or Chevron Ultra-Duty EP #2, also reportedly a great all purpose grease