HELP: Horrible Driveline Vibration

Hello all,

Much needed help, I have a horrible driveline vibration from around 25-35 then again from 70-75. From then 25-35 range it doesn't matter if I am accelerating or just cruising but it's so strong it's felt in pedal and steering wheel. From 70-75 it goes away if I let off of the gas. I have replaced carrier bearing and u joints what do I do?

 

try getting your tires re-balanced? hitting a curb or pot hole could throw a weight off your wheel and cause vibes.

 

did it just start or did you install a lift and now experience the vibes?

 

It's been lifted the entire time I've had it, it has carrier bearing shims so I don't think its the angle. Maybe the whole driveshaft is out of balance?

 

Start with the basics. When was the last time you had your tires rotated and balanced?

 

I haven't, there shouldn't be a speed variation associated with tire balance correct? And then for it to go away upon letting off of accelerator.

 

Tire balancing can do some tricky stuff when it comes to certain vibrations. My Dodge Challenger would vibrate between 45-55mph then at 80-85 mph before I balanced my tires then after then no vibes at all.

 

did you just install the 20 inch wheels?

 

It makes sense and wouldn't hurt to do it but I'm almost certain it's that damn driveshaft it's driving me crazy lol

 

Yeah without me being there and feeling it for myself I wouldnt be able to tell you for sure.

 

It does feel rotational similar to something being out of balance. Can you rebalance a driveshaft?

 

Ive never heard of rebalancing a drive shaft before.

 

Tires it is! Thanks again

 

Did the vibration start after replacing the carrier bearing and u joints?

In that case it could be that you put the driveshaft back together out-of-phase.

 

Same symptoms prior to changing, I changed them because I thought it would fix the vibration

 

I assume it was used with the 6 inch lift installed when you bought it correct?
Were the 20 inch wheels installed when you bought it? Did it vibrate when you bought it?

Drive shafts do not suddenly get out of balance. The weight(s) are usually welded in place.

I am more inclined to think either the 6 inch lift and drive angles. Or the wheels are not hub centric. The wheel balance as covered above would also be a source. And yes a wheel balance can vibrate at some speeds and not others.

 

Wheels we're on it and it didn't vibrate as bad but it was there, I have shims for the driveshaft (I can measure today but they look like 2 inches).

 

sometimes when the tires wear it creates more inbalance, i have lifetime balance and rotation for this reason with a local tire shop.

 

OK, so if we're hearing this right:

1. You bought the truck used with a 6" lift already installed

2. Ever since you bought it, it's had an annoying driveline vibration

3. You're trying to diagnose and fix it, and you tried replacing the carrier bearing and U joints but that didn't change anything

So, what you can do is get an angle finder and experiment with changing the angles - take the carrier bearing spacer out, try different spacers, try shimming the rear axle at the springs.

Basically, you can't win - with a 6" lift - the driveline IS going to be out of spec on some angle or tolerance - the game is finding out where the vibrations are least noticable.

The over-the-top solution is to have a custom one piece double-cardan (CV) driveshaft installed (this requires shimming the rear differential so that the pinion points straight at the transfer case)

http://www.4xshaft.com/driveline101.asp

 

All above statements are correct.
Where do I find a single piece driveshafr and how do I measure for it? Also what do you mean by shimming the rear diff? How would I go about doing that?