02 tahoe- feeling vibration at 45 and up

[aplagens]

Hey guys. If this is a repost, I apologize. i couldnt find an answer on the site, or elsewhere. just chagned out my u joints, and now it feels like the truck is vibrating at 45 or faster.

I can say for sure, but when re-assembling the drivesahfts, one might be flipped end for end. Could this cause the vibration I now experience? It feels like a giant vibrator is on high. Its not in the steering wheel, and this literally started the day after replacing the u joints. I'm new to working on drivetrains, so my best guess is that the drive shafts need to be re balanced due to the hammering and what not to remove the old joints. Anyone else ever experince this?

The new joints are clipped into place, so could the caps need to seat? (Couple of friend suggested this, not really sure if this is the issue, though)

Thanks for the help, appreciate it!

 

[catfish]

try the bearings in the output shaft of the tranny and at the input shaft into the rear-end. grab hold of the drive shaft and wiggle. look to see if theres any play at either. i had same problem and it was the pinion bearing in rear-end. i did it myself but be VERY careful of the parts you remove, the clips that hold the rear together are easy to screw up and lose

 

[aplagens]

Thanks catfish. i'm getting the truck on a lift later this afternoon. I'll look at the rear end, as most people suggest it could be a bad bearing. Is teh input shaft bearing teh one in the tail end of the transfer case? want to make sure I'm looking at teh right parts.

Also, how do I remove the input shaft bearing, if thats the case?

really dont want to pull the t-case out....again....if possible.

 

[aplagens]

So, go the truck onto a lift, and checked the U joints. BAD joint in the FRONT drivesahft. Easy fix.

Think I know what the issue(s) are in terms of a grinding that I hear. rear passenger wheel is loose, like bad axle bearing loose.

Since it was up, I had it dropped into 4 HI, which it did successfully. Now I'm new to 4WD mechanics, so bear with me on the explnation. Paasenger front wheel rotated freely. BUT, driver side did not. As gas was applied, passenger wheel spun, but drivers barely moved. Is this normal for 4WD? I'd assume one wheel locks, but when the entire truck is unloaded? what coud cause this? Also, truck wont come out of 4WD with push button switch. any input on that as well? Again, thanks for the help. Hope to get this motha running clean soon...

 

[catfish]

thats normal for one to turn. if the one that turned with the engine were to be stopped, the other side will take over. its a limited slip differential. your axle assessment sounds logical. loose wheel could very well be bearings are bad. not too hard to do. lot easier and cheaper than the pinion bearing thats for sure.
id say try that first.
as far as the front tires turning on one side, thats normal. leave that alone. dont worry about it until it stops pulling or starts to make popping noises.
a good way to test the 4 wheel drive is to lock it into 4 wheel and turn hard left or right and drive slowly in a circle. if it feels like its trying to pull the wheel out of your hands and jerking, its doing its job. leave it be

 

[aplagens]

Yea, since the 4WD wont disengage, it is working. The axles pop and pull, feel the load as it turns. Carefully drove back to lot, pulled ATC fuse, and have a locked axle that doesn't have a lot of noise or other issues at the moment. Thinking my electronics are fried....investing in a Haynes book to troubleshoot what parts are needed. I've read elsewhere the front actuator can go, and with my truck at 12 years and all 12 in Michigan winters, I'm guessing this can cause failure.

Will me keeping it in 4hi, but no juice via Autotrac, going to at least keep me mobile while I research my options? Dont want anything to explode....

 

[aplagens]

Follow up

Repalced a bad front U joint, new trans fluid and filter, and still cant get the damn thing to come out of 4hi. I pulled the fuses in the side panel as well as under the hood. Will this damage anything since its engaged but no electric power to the t-case? Not sure on this. Thanks!