I just rebuilt both my front and rear driveshafts with NEAPCO made in USA u-joints and Centering Ball. I rebuilt them because I had a vibration coming up through the seat and floor that was a higher frequency than a Wheel balance vibration (plus no vibration in the steering wheel) starting at 23 mph,....up to about 35,......and then again becoming noticeable at about 50 mph as a now much higher frequency vibration,.....

Put the rebuilt driveshafts back on,.......and the vibrations are essentially UNCHANGED.

I removed both shafts and had them balanced.......small weight added where an original weight was now missing on the front shaft, and nothing on the rear shaft.

I re-installed them,.....and still no change. Still glad I did the work and now have a safer greasable driveshaft that won't fly apart and destroy my tranny,.....but perplexed on the vibration.

Any suggestions from you guys who have been down this road before?

Brian in Austin

 

Did you change the rubber coupler?

 

I looked at it, and it looked fine.

 

I have been going thru the same thing. I just found out mine is coming from a bent front output shaft in the transfer case. I took it out and spun it on a lathe to test it, and sure enough, it was bent.

 

How were you able to determine that?

 

The bearing on the output shaft could be bad. I had that issue, after changing the bearing it was all good.

The bearing had no visible wear or visual indication it was bad but after the change it was flawless.

So for sure the vibration is coming form the shafts and not possible wheel?


Also I determined that my front output shaft was bad by removing the front drive shaft and putting on the on the diff lock and drove it with no more vibration since no load was on that output shaft. Try that to determine if its the front or back.

 

Output shaft on what? (sorry if this is a stupid question), Transmission, Transfer case? How did you determine that it was bad? On the certainty of it being a shaft vibration,.....I can't say with 100% certainty, but I have had enough cars with out of balance wheels over the past 45 years of buying and fixing cars, that I've think I felt every possible out of balance scenario. This is not in the steering wheel but appears to be right under the front seats and a much higher frequency vibration than a wheel balance problem.

Also, I have a 2003, so no CDL,.....not even the spud on the Transfer case to manually lock it,......definitely bought the wrong year.

 

if its a rear tire you will fell it in the seat, a front you will fell it in the wheel.
try rotating them front to rear and see if it moves.
you don't have a CDL, but I think you can still pull the rear shaft and drive it? not sure?
did you replace the flex coupling and bushing in the rear shaft?

 

Its the Transfer case where the drive shaft attaches to. Its also where the output shaft is. Its where the bearing is that I am referring to that causes the vibration.

This can be dangerous and all precaution should be taken. Ok, without CDL you will have to put 4x jack stand two in the rear under axle and two in front under axle.

After all wheel is completely off the ground. put in drive and slowly increase speed to find the vibration. Have someone stand on the side NOT in front or back of vehicle!! and look and listen. If it cannot be determined

Then lower two rear wheel but leave the front wheel up in the air. If you don't have CDL or any traction control etc. The front wheel should spin and no power goes to the rear wheels because you have no CDL which means the rear drive shaft will not turn while all the power goes to the front wheels. If the vibration occur during the test its the FRONT transfer case output bearing that is bad.

If nothing, lower the front wheel and raise the rear wheel and repeat the process and if it vibrates its the rear output bearing.

If neither of those technique could determine the vibration let me know.

Here's how to change the output shaft bearing
How to Remove/Renew Transfer Case Front Output Shaft Bearing

I've done it myself, took maybe 40 minutes? I wasted alot of time trying to pull the shaft out when it was caught on something inside lol stupid me. I twisted the shaft a little then pulled and it came right out.

 

A huge Thank you for sharing the procedure for testing and repairing the bearing(s).

Was there any tendency for the truck to move and/or come of the jack stands when you had one axle down on the ground and started running up the rpms?

Brian