Strange vibration that began about two months ago. Gradually increases from 35 mph and gets worse until 45mph. When the trans (auto 48re) shifts around 40-45mph, it goes away.

I notice the vibration mostly in my cup holder as it starts to shake with the vibration, however it does vibrate the steering wheel and seat a little bit. I thought it may be that my tires are down to their last 20% on tread or that they're out of balance/alignment, but I would think that the vibration would increase with more speed and not go away when the trans shifts.

Anyone with any ideas or similar experiences? Thanks guys...

 

May sound weird, but I would check your u-joints. They may seem tight, but look them over really good. My truck does this when they are getting worn. I have replaced 3 sets of these, same symptoms every time. If they pass, I just changed my front end components, bearings and ball joints. I still have a little play. Also look at the top pinned thread on the main paig of this particular forum for death wobble.

 

Thanks hot_runner58, will check the u-joints. I have 90k and have not replaced them. I did the front end swap, ball joints, etc too recently so I think that stuff is good.

 

when you feel the vibration, is it in the steering wheel or floor board(front tires)

or can you look in the rearview mirror and see the corner of the bed shaking? (rear tires)

could be something as simple as lose of a wheel weight off a tire.

if drive shaft is good then tires would be my next look see.

real pain in the butt when you have a shimmy at a certian speed.

If you have been on some rough roads you could have lost a big chunk of rubber off a tire. some of those tires with big lugs, the lugs can break off causing vibration.

let us know what you find causing the vibration.

 

check if the vibration is consistant with rpm in different gears or constant speed in different gears. ujoints will be more speed specific, drive trane more rpm based. I just fought a similar vibration around same speed but found it to be rpm based as it would happen in 2 and 3rd. as soon as torque converter locked it would get real bad. also check to see if it happens worse under load or lightens when you let off throttle.

 

Thanks for all the suggestions guys. At this point, I can rule out wheel bearings and alignment issues. I will road test today and see if it is more speed or rpm specific. I also am going to crawl around underneath and look closely at Ujoint and center bearing. I'm hoping it's that an not something inside the trans...
Standby for update

btw Junebug- I'm going add my failed parts laundry list to my tag at the bottom too. Funny how so many of us have replaced the same crappy parts.

 

Did you figure this out yet? I have a 2nd gen with same symptoms, but mine is more noticeable at 35-40, and then is noticeable again at around 62-70.

 

MAke sure to check front drivesahft.. I have seen user when this shaft goes bad and destroy transfer case.. Expensive problem for a $$ ujoint or CV joint to fail and destroy transfercase.....

 

Thanks for all the tips guys. Here is a follow up: felt the u-joints with the driveshaft on the rig- they felt fine. Looked closely at the Ujoint that goes into the pinion on the rear diff: rust dust and very dry looking. Pulled it off and felt it- TOAST. Took it in and had new ujoints pressed in- no more vibration or coffee spill. It is smooth as silk from 30-45 now. There is a very slight vibration at 65ish, but hardly noticable. Since it's easy, relatively cheap insurance, I'm going to pull the front driveshaft and have the Ujoints on it done too. Thanks again guys and if anyone else is experiencing this- go straight to the Ujoints. Later

 

Thanks for all the tips guys. Here is a follow up: felt the u-joints with the driveshaft on the rig- they felt fine. Looked closely at the Ujoint that goes into the pinion on the rear diff: rust dust and very dry looking. Pulled it off and felt it- TOAST. Took it in and had new ujoints pressed in- no more vibration or coffee spill. It is smooth as silk from 30-45 now. There is a very slight vibration at 65ish, but hardly noticable. Since it's easy, relatively cheap insurance, I'm going to pull the front driveshaft and have the Ujoints on it done too. Thanks again guys and if anyone else is experiencing this- go straight to the Ujoints. Later