The joints that have the plastic injection pin are only on driveshafts that are installed at the factory. New u joints (universal joints or cross bearings) that are sold as replacements will have a retainer clip installed in place of the plastic injection pins. They have factory-sealed grease in them and are non-greaseable types of bearings. If you want to do it yourself, you will need a press or large vice on a workbench to do the job. I used to do them myself in my younger day, but now leave that job to a machine shop that has the proper tools and knowledge to do it without damage. Getting them apart isn't the difficult part, but getting the new bearings in is where it can get hairy. The same goes for the carrier bearing.
With the driveshaft in the vehicle, push on the shaft at the bearing location and see if there is movement in the axis of the bearing, and then rotate the shaft 90 degrees and do it again. If it is tight, then don't mess with it. If you decide that you want the U joints replaced, then find a shop that can balance the entire driveshaft also.
Changing the pinion shaft bearing isn't as difficult a job if you have a drive-on lift to work off of. You will need to mark the pinion shaft and the nut, and then count the number of revolutions of the nut as you remove it, so you get it set correctly when you reinstall the nut. Behind the nut is what is known as a crush collar, which is set when the original differential gears are installed, and you don't want to disturb that setting. Once again, if you have never done one before or assisted someone that has, it is better left to the people with the proper tools and knowledge. If you mess it up, it can get expensive quickly. I was taught how to remove and replace the nut by an old-time experienced mechanic when I was young, but today I wouldn't think about doing one again.
The last time that I had to do one was on my former 1963 Chrysler New Yorker ambulance, which also needed axle seals. What I thought was going to be a fast and easy job turned out to be a complete rebuild, and took me a week to complete. I opened a can of worms that was difficult to get all the worms back into. Someone had been in there before me and didn't know what they were doing, so the entire unit had to be replaced, and like the Cadillac commercial chassis differential, the Chrysler unit was also as scarce as hen's teeth.
If you decide that you want to tackle either of these projects, I suggest that you call Dan Scully, our PCS technical advisor, and discuss it with him and then decide how you want to move forward.
Best of luck to you.
Paul
