Forums Forums (
-   2500HD/3500 HD Trucks & Drivetrain (
-   -   Hunting a Vibration (

richp 11-16-2016 12:11 PM

Hunting a Vibration

Long story coming...

I've got 107k miles on the '09 in my signature, lots of it towing a big fiver. But it's been maintained well, all service at the proper intervals, etc. Overall a good performer.

Two months ago, I had the tires rotated. Not long after, I noticed a vibration in what felt like the rear at most speeds above 35 mph. Putting the truck in neutral at highway speeds and revving it did not change the vibration, which is more "seat of the pants" than "shake your sunglasses off the dashboard" in nature. It was sort of subtle and our roads are miserable and that might have just been confounding what I was feeling, so I took the truck on a 1,000 mile interstate trip at 70-75 mph, during which the vibration didn't change much.

Got back home, and had the tires rebalanced at Firestone. No real improvement.

Went to my Chevy dealer -- Bob Jass in Elburn, IL, which has given me decades of good service. They checked the motor and transmission mounts, exhaust hangers, looked for leaks at the seals in the transfer case and differential, and balanced the tires again. No real improvement. After several test drives with the service manager, we decided that it could be a driveshaft out of balance; it was very rusty and had done a lot of heavy towing. Off it went to a driveline specialty shop, and they recommended replacement, which we did, along with new U-joints of course. No real change.

The dealer then did a road load balance test on the tires, and concluded at least two of them might have a slipped or damaged belt. He then pulled the new tires off another truck on the lot, put them on mine, and we drove it again. Some of the vibration went away, but not all of it.

Back to Firestone. They listened to my account of everything I had done, and offered to fully warranty the tires, no further questions asked. (Two were 18 months old and the other two were 40 months old. As with my Chevy dealer, it pays to have a longstanding relationship with your tire guy also.) So for their mounting and balancing cost, I got four new tires. But I didn't get improvement in the vibration.

Back to the dealer for more road time. This included getting it up to 60 mph and shutting off the engine in neutral to see if the vibration went away. It didn't -- suggesting it's something in the driveline that moves even when the engine is out of the equation.

The vibration did change somewhat after the new tires were put on. It is accompanied by a very low noise, and is only barely felt in the steering wheel. It now is almost like I had put snow tires on the truck, even though these are a street pattern. The seat of my pants tells me it's coming from the rear, and if the driveshaft and U-joints were not brand new, I'd say it was a U-joint going out.

I want to cure this before I start towing my fiver to Arizona in January. But there seems to be nowhere to go now but to start tearing down things that show no outward sign of being the cause -- looking for a bad bearing that is early in the failure stage, for instance. So we are stumped now.

Which brings me to you guys. Any fresh ideas would be greatly appreciated.

Thanks in advance.

rapidoxidationman 11-16-2016 04:54 PM

Is your rear differential fluid sparkly at all? (metal powder or flakes from a bearing)

richp 11-16-2016 07:14 PM


I asked that very question today.

I was assured that when they changed all fluids as a separate service event a few weeks ago (antifreeze, differentials, transmission, transfer case), all liquids were normal in appearance for the amount of mileage since the last change.


richp 11-19-2016 02:15 PM


No more ideas from anyone?

Dmaxmaverick, have you ever encountered anything along these lines?


convert2diesel 11-19-2016 10:34 PM

Granted it was on a car, 94 Cadillac, but chased the same kind of vibration. Went through exactly your process, though I didn't use the dealer. Finally traced it down to a faulty shock on the rear. 1st 1 inch of travel had no resistance so even a small imbalance in the tire would cause that tire to vibrate ever so slightly and created a hum or buzzing sound from the driveline. Drove me crazy.

Changed the shocks and it went back to driving like a Cadillac.


DmaxMaverick 11-20-2016 07:56 AM


Originally Posted by richp (Post 316259)

No more ideas from anyone?

Dmaxmaverick, have you ever encountered anything along these lines?


You've covered most of the usual suspects. Tires, wheels, rear shaft, joints. Because it's specifically speed related, it's most likely downstream of the transfer case. Just because it "feels" like it's in the rear, don't rule out the front. Check the front end and front shaft/joints, and make sure it's completely disengaged when in 2wd. Noticeable vibration is normal when in 4wd at 35+ MPH, and it can carry throughout the chassis. Other than that, maybe a front or rear hub/bearing. Less common would be a pinion or carrier bearing, but they are usually more load-related, and less related to speed.

Also check the lower air dam, fog lights (if installed), and fender tubs. Make sure they're secure. Just because.

richp 11-20-2016 08:33 AM


Great info. Thanks a lot, both of you.


dually2002 11-20-2016 02:06 PM

I have had a vibration in my truck ever since I purchased it with 25k on it. The vibration is felt in my butt. From about 43 mph to 57 mph (empty) it is felt. Back in the early 2000's there was discussion on here about what the engineers called frame beaming. Vibrations in the frame at the same speeds do to I think the hardness of the steel in the frame. I am sure some one can explain it properly. Don't know if that is the problem but its an explanation that gives me piece of mind.

richp 11-20-2016 03:03 PM


Thanks -- I've read about the beaming, and considered it.

But this is a problem that emerged after 105,000 miles of non-vibration, so unless there is another element to it, I've been looking in a different direction.


richp 12-01-2016 06:56 PM


We have a solution!!!

After replacing the tires, the nature of the vibration changed. (Recall that it was about this time, the OEM driveshaft was replaced.) Another couple of dealer visits ensued, to no good effect, with a halt for Thanksgiving week.Then it went back to the dealer this Monday, with the thought of following through on Dmaxmaverick's ideas.

But before they started tearing the front end apart, they came up with one final test, using a new diagnostic tool they dug up from somewhere. They put the truck on a rack, pulled the tires, and hooked it up to a set of computer-linked vibration sensors. The resulting bar graph clearly showed the vibration was in the drive shaft.

So the new shaft came off, and went back to the shop that built it. Lo and behold, the u-joint cradles had been welded out of phase.

Another drive shaft -- this one properly done -- was installed today, and it's driving like it should.

So my originnal problem was two-fold -- one or more bad tires, and a bent driveshaft. Some of the problem went away with the new tires, but the bad new driveshaft muddied the water for a while, making it seem like there still was a third problem that needed fixing.

So, there you have it -- a long, convoluted situation finally fixed.


All times are GMT -7. The time now is 11:42 PM.

Powered by vBulletin® Version 3.8.2
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Copyright 1996-2018 by - All Rights Reserved