front driveshaft u-joint failure...

I just found that the back U-joint (where it goes into the trans. case) is gone on my 98 4dr. Tahoe. The truck does have 140K on it, but I was surprised. I have not heard of this u-joint failing before. Have replaced my rear shaft u-joints at about 100K. Does this shaft rotate even while you are in 2wd setting on the buttons? (can't get my head down there while I'm driving!! :) Spun it by hand while in neutral and it is running out about 1/4"!

Any special notes on removing this shaft or u-joints? I have the push-button 4wd, and there is some sort of rubber belows-looking cover on the yoke where it goes into the t-case. This end seems to be quite loose also. Does this just pull out like the rear shaft? Do I somehow need to remove this bellows cover to replace the joint? Don't want to damage it while heating the plastic retainers on the u-joint caps...

Well, talked to my GM dealer last night and he surprised me and said it would be easy for me to do myself and save a lot of $, so that's what I'm going to do. He said as long as I can unbolt the front of the shaft and slide it back out of that front yoke on the front diff. (mine did) That means the slip-joint going into the transfer case is free. Sometimes those are jammed and then you are screwed I guess.

Will pick up a new U-joint and will probably replace Wed. eve. Will update more later. Any other concerns or comments, fire away!

I just found that the back U-joint (where it goes into the trans. case) is gone on my 98 4dr. Tahoe. The truck does have 140K on it, but I was surprised. I have not heard of this u-joint failing before. Have replaced my rear shaft u-joints at about 100K. Does this shaft rotate even while you are in 2wd setting on the buttons? (can't get my head down there while I'm driving!! :) Spun it by hand while in neutral and it is running out about 1/4"!

Any special notes on removing this shaft or u-joints? I have the push-button 4wd, and there is some sort of rubber belows-looking cover on the yoke where it goes into the t-case. This end seems to be quite loose also. Does this just pull out like the rear shaft? Do I somehow need to remove this bellows cover to replace the joint? Don't want to damage it while heating the plastic retainers on the u-joint caps...
the front drive shaft has a slip yoke on it and on that yoke is a gease fittin make sure it is geased it is easy to replace the u-joints replece both not just one

the front drive shaft has a slip yoke on it and on that yoke is a gease fittin make sure it is geased it is easy to replace the u-joints replece both not just one

Yes, that's true some do have a grease fitting, but mine does not. I believe it is because it is the push-button with auto-trac, but not sure. Mine has a slip joint on the yoke going into the transfer case, covered by a bellows (cv joint type) cover. You can only grease it by taking the shaft out...

Completed the mission last night, 4+ hrs. as the u-joint was rather tough getting apart. My bench vise jaws were to narrow to press the complete joint apart, so I ended up hacking it into pieces with my 4' angle grinder, being careful not to nick the yokes at all. That way I could heat and press out each individual bearing cap. Much easier!

Re-assembly was a breeze. Bought the heavy-duty style joint at Napa $21 ea. Why don't they just put these internal c-ring retainers on at the factory!! Was able to find a cv boot style clamp at Car-Quest the correct size to slip over the protective boot, and clamped snug with a nippers and a vise-grip pliers. Rides smooth and quiet now!

hey spruce, thats great to hear hope i help a little ..............tommie99

want to know a gm u-joint secret??? they inject plastic into little holes in the yoke to hold the caps on which makes them hard to get apart. a little trick we used to do at the shop was heat the yoke untill the plastic shot out then you could easily tap them out with a hammer and socket. glad to hear you got it replaced.