Expert: Ken Surerus - 4/7/2005

Question
1995 Ranger 2.3L,2wheel drive,.Ext cab,Manual trans.
 Have noticed a vibration for a while but am now trying to solve it. Vibration in drive train most noticable above 45MPH. Found center carrier bearing worn out and replaced same. Reconnected and ran with no improvement.
Disconnected and removed rear shaft between carrier bearing and drive axle. Ran(on jacks) with no improvement.
Replaced front universal (between trans.ext and carrier bearing) and ran with no improvment.  
Tried shimming carrier bearing with no improvement.
Vibration not evident when drive shaft is removed from trans extention.
Do shafts require balancing like wheels?
What should be tried next?
Only repairs done which may be associated was a clutch replacement by Ford a couple of years ago. (I noticed the rear trans support bolts are about 3/8" from  the original position)

Answer
Mr. Reed,

It sounds like you have a bent drive shaft. The best way to find out is to take your drive shaft to a machine shop and have them turn it. Yes, there are weights on a drive shaft that help balance it. Other things I have noticed, a bad rotor will give you the vibration or a bad wheel bearing will also give you a vibration. Hope that this helps and if you need further assistance, please do not hesitate to contact me. Good luck.


Ken