front driveshaft u-joint failure...

[sprucegoose]

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...

[sprucegoose]

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!

[tommie99]

Originally Posted by sprucegoose

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

[sprucegoose]

Originally Posted by tommie99

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!

[tommie99]

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

[amac209]

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.