I'm currently having the rear end rebuilt, pinion bearings,carrier bearings,axle bearings collar etc. The outer pinion bearing was pitted. Could this cause a drive line vibration similiar to a u-joint? The shop is telling me the u-joint seems to be fine. any help ??

 

Of course it's possible, no bearing should be pitted.. But since the shaft is out,why not put new joints in?

 

Normally, that vibration is due to an out-of-balance driveshaft. Over time, it rusts, picks up all kinds of deposits and becomes unbalanced. I had it happen on mine. Re-balancing the shaft will eliminate this. Now, it may not be that in your case so, just keep that in mind.

CM

 

I've heard that before too. if it were the drive shaft out of balance wouldn't it have the vibration al the time. Is it a possible torque converter shudder maybe locking up going into overdrive???

 

When do you get your vibration, and what have you done to troubleshoot it? Could be as simple as a wheel out of balance, or as bad as the rear/front end being buggered. Since you are having the rear rebuilt, see what happens when you get it back.

 

just got off the phone with the dodge dealer they said the shudder is still there after the rebuild in the rear end. How big a deal is balancing the drive shaft?

 

No. Depending on the resonant frequency of the vibration vs. rpms of the drive shaft, it will "walk" in and out of resonance zones.

Let me explain it better. If the shaft is not aligned or balanced properly, variation in the yoke angle will show up as un-cancelled / non-phased out vibration. In order to get the most effective cancellation, the yokes must be aligned with one another. Unequal operating angles result in a vibration that increases with shaft RPM, while phasing problems may be felt at lower RPMs.

So, what can happen is, it will either show up at higher RPM loads and really resonate uncontrollably (SHAKING) or, it will show up along multiple resonant frequencies as rpms increase as did in my case.

I had a low vibration around 1600 rpm and it went away totally at 2100 rpms. It later re-appeared with greater amplitude (louder) at ~2500 rpms. Above that, it went away totally. The third time was the charm at around 3000 rpms to which, the amplitude was much higher, the whole vehicle was in resonance with this shaft and, it was mechanically starting to stress the bearing at the differential to the point of oil was leaking out around the bearing.

I had a specialty shop clean mine, coat it, dot it, strobe and balance it along with all new U-Js for......400.00 for both drive shafts.

Balancing only was a lot less.
CM

 

Same issue I had when I first got my 98. Shaft was bent and out of balance. But I would do this one step at a time. The OP is already having the rear end done. I'd wait and see how it is after the rear end is done. Of course it wouldn't hurt to have the DS checked while it's out. But then, you'll never know what the real problem was.

 

Hey! welcome back cmckenna!

 

I believe the OP stated earlier that, the dealer finished the rear end and, the vibration is still there.