U Joint Help

[Atc1armyb]

I had a friend of mine install new U joints for me cause they were squeaking and he needed some extra money.. Now my truck is vibrating so bad I can hardly drive it without wanting to beat my head against the steering wheel. The worst of it is 45-65 mph. My truck never vibrated at all like this before, what did he do to me and how can I get right again??
Please help
I have '02 FX4 SCAB if it makes a difference
Thanks

[torkum]

Did he index the shaft before taking it out?

[rmac]

I have a 03 KR Screw and I have the same problem. I changed the U-Joints, new tires and balance and still have this vibration in the rear.
How would indexing the drive shaft where it slips into the transfer case make a difference? The slip joint shaft is not keyed. I'm thinking that the drive shaft needs to be balanced especially if you needed to beat the u-joints at all. I know I had use a big hammer a few times during the installation.
Is there any way to know if the drive shaft is installed incorrectly.

Thanks

[Bindernut]

Another thing to check for is if any of the u-joints are "tight". This can happen if the cups aren't seated properly, or if one of the needles is trapped in the bottom of the cup instead of along the sides where they should be. This would be the first thing that I check especially if the ujoints were pounded in instead of pressed in.

I have noticed a few times that improper indexing will cause a vibration too. Older MoPars had a keyed spline joint to prevent that up front, but not on the other end of the shaft. Not so with Ford and GM that I've ever seen. But...what happens if you swap in a new tranny, transfer case, or gear set? Obviously can't reindex then so it might take a bit of trial and error to find the "sweet spot". I.E. drop the shaft, rotate one spline, reinstall, and road test...repeat as necessary.

I think the indexing procedure mostly goes back to the days when the slip yoke was on the driveshaft itself (between the two ujoints). On a shaft like that it is mandatory that they be indexed so that the joints line up with each other. Any error there and the shaft will eat u-joints, vibrate like crazy, and take out tranny or pinion shaft bearings!

[Atc1armyb]

I doubt that he indexed it, but the cups all do seem to be seated properly. Do you guys suggest just taking it somewhere? Is it possible to line it up at this point without all of the trial and error? My dad mentioned something about "timing" the U-joints so that they are in the same position, ever hear of this? Thanks for the help everyone

[scouty]

I just replaced mine, I took the drive shaft out my self, didn't index them this is the third time i've done this not on the same truck but both were 99 f150
4x4's, then I had a mechanic press them out and the new ones back in. everything is ok. maybe the shaft got dented that will throw off the balance? Just a thought.