Just thought I'd post a note about the failure with my front drive shaft. Seems the slip yoke has got too much play in it. I had to replace my rear shaft a few years ago for the same problem. I've greased them under my care every 5k which is since 38k. Actually I probably missed a few along the way. Both shafts had perfectly good u-joints from what I could tell, but there was quite a bit of play in the yoke. What I do to check this is to grab onto the front of the outer shaft near the end. Now moving the shaft up and down feel for movement. You'll want to reposition you hand back slightly and check again and then repeat. There is definitely a "sweet spot" where you will feel the most movement if the yoke is worn. I have had some minor vibrations at highway speeds when I let off the gas. But this weekend with the first camping trip there was a period where the transfer case lever was shaking more than normal and some vibrations were felt. This was while pulling a trailer. And no I don't field strip the shaft when I want to grease it. I just pump in fresh grease through the zirk until the shaft starts to expand and then drive it. There is a nice grease ring where the grease is flung from the other end so I'm sure it's getting lubed. This might be something to check.