Last night I pulled the r front axel with hub still attached, pressed out old u joint that was clanging because it was so shot. Pressed in the new u joint, cleaned up and greased the shaft, splines and hub bore. I re assembled everything with no issues, torqued hub bolts an caliper bolts per Haynes, remounted wheel and went for test drive. after about a mile sudden massive vibration out of right front. I came to stop, pulled away and all ok for about another mile, then same thing. I tried 4 wheel high and no problem... went back to 2 wheel, went a ways and vibration was back. went home pulled it all apart , cleaned shaft splines etc, rotated hub clockwise 1 hole and remounted. went for test drive got about 5 miles and it happened all over again. tried 4 wheel high and low - both seem to work and no vibration....what to do? could the bad u joint have done other damage? but the severe vibration didn't start until AFTER I replaced u joint. oh yeah, I don't seem to have any fluid leaking... some advice/ideas please.

 

Is the u-joint getting hot, and binding? If, when it starts its vibrations, does turning either direction make a difference?

 

u joint flexed all directions when I pulled axel and hub. turning doesn't seem to help. slowing to complete stop or almost complete seems to "reset" to normal and then cycle starts over

 

so I guess Ill pull it apart again, clean it and rotate the hub mounting one hole clockwise... I just don't know what is going on? Is it possible that a bushing in the intermediate shaft is moving in and out of position? The vibration is loud and speed sensitive and is not affected by braking except that it stops once the vehicle has stopped. One thing I noticed is that there was no boot/seal covering the outer end of the axel tube. It was pretty dirty in the tube so I scraped and vacuumed out all I could....

I hope some of you guys have an idea or suggestion for me. I don't want to throw money at a problem that I should be able to handle.

 

when you took the u-joint apart and put it back together again - did you mark the relationship of the 2 axle halves, and then put them back together in the same relationship. if not, then it might contribute, but as far as i know the axle halves are not balanced like a drive shaft might be. i doubt this has anything to do with it, because people change stub shafts or inner axles all the time. i'm just typing while i think.

you said passenger side. when you reinserted the axle, did it align onto the collar inside the cad ok, and did the hub bearing seat into the steering knuckle completely and squarely.

did the u-joint go inside the caps ok, and did the inner clip snap into its groove, ensuring that a needle bearing didn't fall into the bottom of the cap, letting all the other needles get skewed.

 

you mentioned bushings. there are 2 bushings inside the cad. one in on the inner (intermediate) axle to hold it in place. the other is the little one in the end of the outer axle, which interlocks with the inner axle and holds them aligned.

any chance the small bushing fell off and the outer axle is flopping about in relationship to the inner. -this is the most likely.

pull the cover off the cad and look at the junction of the 2 axles. if you can see them.

 

no rubber boot at the end of the axle tube is normal. its open so the rocks and mud and water and sticks can all freely float into and out of your axle tube. pretty stupid but that's how it is.

 

Yes I did mark the relationship on the two halves and was careful to put it back together with same relationship. When I first seated the u joint in the ears of both halves, it was bit stiff but not bound up at all. As I flexed the joint it got looser. The half moon clips were installed and well seated on all four arms of the u joint. Both times I re-inserted the axel it went in smoothly I had to rotate it slightly to so that the splines would match up and then it slid right home. Yes the surface of the hub/bearing assembly squared up nicely and I torqued them to 125 pound feet after snugging them down.

I'm gonna pull it apart again and I will re-examine the u joint to make sure it is not binding. But I feel like if it was binding it stay bound, not be ok then bad, then ok then bad...

I am open to any ideas! I enjoy working on trucks and tractors, but I am no master mechanic. I really appreciate what I have learned on this forum in the past month! I did rear brakes, rear propeller shaft (u joint disintegrated and dropped the shaft), repaired emergency brake, repaired exhaust which had separated at a joint. Have changed all fluids except brakes and front diff.

 

the 2wd position of the collar and fork is on the passenger side outer axle. when you shift to 4wd, either low or high, the collar/fork move towards the drivers side to engage with the intermediate axle.

so before removing the outer axle, shift to 4wd and roll back and forth and wait for the collar to engage (4wd dash light comes on). then turn off ignition. this "parks" the collar/fork onto the inner/intermediate half of the axle. This prevents the collar from falling out of the fork and into the bottom of the cad when remove the outer half of the axle.

i don't believe that rotating the hub bearing one bolt hole is doing anything for you since its stationary.

a fallen out small bushing is most likely, but when i changed mine it sure as hell wouldn't fall out. i had to cut it out.

 

The shift fork, collar, and bushings inside the CAD is sort of what I was thinking. As I was mentally reviewing when the vibration would begin, it seemed like it happened mostly after a bump in the road which seems consistent with the shafts popping in and out of alignment.

SO you are saying I should, get it to lock into 4 wheel drive. then pull the axel and then open up the CAD to look for a slipped/dropped bushing? If I cant see a slipped/dropped bushing I should re-assemble and drive a bit in 4wheel, then shift to 2 wheel and see what happens?

Thank you!! I really appreciate your help!