Vibration from rear?

[jsepps]

My gf's 2002 got some noise coming from the back. I'm not a mechanic and I've been working out of town so I don't have much time to look at it. It's not tire noise and I can't see anything obvious. When I put the transfer case in neutral the sound seems to go away when coasting.

Any ideas ?

Thanks

 

[cplchris]

First I would check the u-joints on the rear drive shaft (connects the t-case to the rear diff)...I just did mine yesterday pretty easy job and cheap.

 

[jsepps]

Thanks , U joints were my first thought but there doesn't seem t be any play in them. I will probably just change them anyway to see if it fixes it

 

[cplchris]

the u-joints won't have play in them...they will be really tight/hard to move...it is easier to judge them if you disconnect the drive shaft from the rear axle and try to move the joint by hand.

 

[dude1116]

Just had a similar problem. It's either the U-joints on the rear drive shaft (that was my issue. One end was seized in one motion direction.) or the t-case end CV joint. You can check that by looking at the joint to try to find a tear in the boot, or just removing the front drive shaft completely to see if the noise goes away. Being that you say that it's coming from the back, I'm guessing U-joints. Mine also had no play in them.

 

[LibertyFever]

My company vehicle is a 2013 Dodge Minivan. Since I picked it up a month ago it's had a bad vibration at highway speeds. Immediately i suspected an imbalanced wheel. I've had this happen before.
I took it to the dealership (it's still under warranty) for them to balance all four wheels.
I was surprised to learn that my problem was with dirt & mud caked inside one of the rear rims, imagine?

So it might be worthwhile to check the balance of your wheels too.

Regarding a bad u-joint, shouldn't the vibration be only present while you're accelerating or gearing down? You can easily check the u-joints. Just crawl under your Jeep and try moving the driveshaft. There shouldn't be much play.


Sent from my iPad using Tapatalk

 

[Porkchop]

U joints don't have to have play in them to be bad, I've felt a lot of hot u joints that had no play. I'm sure given enough time they would have play in them.

 

[cplchris]

why does everyone think that a u-joint has to have play in it for it to be bad?

 

[dude1116]

My U-joint was stiff as hell (giggity) when it was broken. Pulled one of the caps and the needle-bearings came out in a cloud of rust and dust.

 

[FenwickAngler]

Does it sound like your driving over a rumble strip?

might it be happening roughly around 40-55 mph?




Might be your torque convertor. i.e. might be time to rebuild ******.

 

[CactusJacked]

With an old dry u-joint, the needle bearings can make chatter marks (ridges) on the trunnion (the part the needles ride on). If you had the joint in your hand, you'd be able to feel the chatters as you rotate it back and forth. That's where you can get the vibrations from. You won't be able to tell when it's still all attached, and the joint doesn't have to be sloppy to be bad. I know I have some old take-offs laying around here (somewhere) for show & tell. I always use greasable u-joints with the zerk fitting in the end caps, not in the cross which is weaker. Although, I don't feel the "stump pulling torque" of our 3.7 () is going to compromise one of those types of joints, but still, I have my druthers.