Had the rear u-joints replaced recently at Firestone. Was OK for 2 days until driving on the highway I heard what sounded like a gun shot and then some very serious driveline vibration. I pulled over, one of the caps from the u-joint at the CV to driveshaft was missing. It got fixed but now have driveline vibration. I finally found a shop that could balance a Toyota shaft with CV joint - they balanced it, straightened it (said it looked slightly twisted) and told me long as it was off the truck, I should replace the moderately worn carrier bearing which by the way Toyota is getting $170 for these days. I put it all back together only to have the same amount of driveline vibration.

So I started adjusting the carrier bearing alignment. You can almost double the amount of drive line vibration when the bearing is grossly mis-aligned. I almost had bearing aligned where I could live with it before applying the ôfinal tweakö that totally messed it up. Using the FORCE to find the sweet spot isnÆt working out, who knows the secret?

I don't think there's too much to the carrier bearing alignment- your problem is likely elsewhere. Check the t-case and pinion flanges for looseness, spin the shaft and check for any wobbles, re-check the u-joints for any looseness, make sure the CV is solid, etc. The driveline shop should have checked all that for you though. And if the shaft is really twisted, it is probably weakened and will only get worse and should be retubed or replaced.

Yep, he's right. Carrier Bearings and mounts are there to take up vibration (really there to make sure the shaft is not too long and the angles to the u-joints are not too steep). Same thing in the end. You have a wobble, look elsewhere. You may have popped another u-joint. They all get the same basic wear. One dead, generally all dead or getting close.

Appreciate the ideas - your both most likely correct. When I saw how much more it shook when the bearing wasn't centered I started thinking it was a real critical deal to get it exactly right. So I got a laser level and aligned the center hole of the bearing with both halfs of the drive shaft and then centered it crossways sighting on the 2 mounting bolts. It still shakes. Put it up on jack stands and started it up, can see a definate wobble in rear half of drive shaft at the CV joint. Something in it or the tube must have twisted when the u-joint cap popped of at 70MPH.

I'll take it back to the driveshaft shop and complain but I have no faith that they can fix it or they would have done it the first time. On EBAY I see there is a new rear drive shaft with CV that will be custom sized for $300 from some place in Utah. Anybody ever have to replace one?

I think your best option would be another stock shaft from a junkyard.
Try http://car-part.com/

Just make sure you keep them lubed (I do mine at every oil change, as do most shops that aren't cutting corners) and you shouldn't need to be replacing u-joints.

He's right again - hope it does not go to his head....Anyway, a loud bang in a drive train is usually associated with a ruptured u-joint. Blown up a few in my time with hi hp motors...Anyway, you probably have a slightly bent shaft or a twisted/broken yoke. I have done it. In my area we have a dynamite shaft shop that does perfect work - called U-Joint Sales and Service. They work on everything from race cars to dump trucks. Build custom or repair stock. Ask dirt or asphalt racers where they go. Firestone and related type shops typically have personnel good and changing oil, shocks, tires and exhaust systems but not really good at true mechanical things. And CV joints are up there in the specialty group. (U-joints are easy). I would go back to them and complain and tell them to get it right even if they have to sub the job out to a qualified shop. It's your money already spent.....They should have road tested it and fixed it the first time. - Anyway, if you need a lead - ask a racer. Their lives depend on a good driveline.

I did read somewhere that the carrier bearing will cause a vibration if not aligned left to right. The procedure was as follows:

Tape a string to the center of the bottom of the differential flange.
Run the string to the bottom of the transfer case flange.
Loosen carrier bearing and align the center of the bottom of the bearing with the string.

I tried this on my truck and it is very difficult to tell where the center of anything is. I did align it but my vibration is still there. So I guess the advice the others gave is right on the money. I would think it would help wear issues a bit if it were way off.