drivetrain vibration

[denialfans]

I purchased a '99 Tahoe 4x4 with 110,000 miles on it back in March and noticed a vibration when going over 65 mph. The vibration has gotten worse, now I can feel it between 22-30 and I can't figure out what is causing it. I read several threads and have tried most solutions, including:

rotate and balance tires (285/75/r16),
wheel alignment,
tried a completely different set of wheels and tires (32/10.5/r15),
replaced all four u-joints,
replaced all four shocks.

It is a little better, but, I believe the new shocks are absorbing the vibration better than the old ones.

I also put the back end on jack stands, removed the rear wheels, and had my wife get it up to speed. I didn't see anything unusual but, I noticed the vibration when touching the body and also when touching the front wheel.

I am considering changing out the motor mounts and the transmission mount because they have alot of miles on them.

I have not had much experience with working on four wheel drives and am at the point where I may need to take it to someone to help diagnose the problem.

Any else had a similar problem? Any other solutions?

[010175]

I am not sure this will help, but I have a 1996 2 door Tahoe with 175,000 miles. Mine has a vibration in it that starts at 65 MPH and will stop when going above 73 MPH. After lots of checking it seams to be torque converter shutter. If you fix it please leave a post as to what it was. Thanks Dave

[andjh123]

Originally Posted by 010175

I am not sure this will help, but I have a 1996 2 door Tahoe with 175,000 miles. Mine has a vibration in it that starts at 65 MPH and will stop when going above 73 MPH. After lots of checking it seams to be torque converter shutter. If you fix it please leave a post as to what it was. Thanks Dave

Very interesting...I've got the same thing on a 2dr '98. It's very noticeable by kind of humming sound as well as vibration in the steering column, rear-view mirror and gas pedal. Starts at almost exactly 60 mph and completely goes away at 68 mph. Only difference is that these vibrations began after I had to get a double-cardan CV joint due to an excessive trans to driveline angle following installation of a lift kit.

[txgearhead]

I've got a 98 2dr 4x4 Auto Mine shakes like a manual transmission in too high of a gear after staying at about 2400 RPMs going up a semi-steep hill. If I coast for abit after tit starts, it returns to normal. Today, the 'Service Engine Soon' light came on (I was actually happy about that) right before the shutter stopped. Without fail, before I could get the codes read, the service light went out....
Anyway, here's an excerpt from some GM docs... Right Click/Save As

GM Service Info #1

GM Service Info #2

[GiGsolydCustoms]

i had that problem before on my astro van. it turned out to be the driveshaft. the balence weight had broken halfway off and was creating a vibration at high speeds. if you look on the shaft ,there will be a small metal tab with 2 small welds (tacks) on it. american axel corp. is the mfg . of most of the chevy driveshafts and they balance every d.s. like you would a tire.a new d.s. for my 2dr 97 tahoe is 135.00.
other than the d.s. i would look into the front bearings or cv shafts,and boots. i hope its a d.s though. the 4x4 fnt bearings arent cheap and are a pain to change. g/l

[denialfans]

Thanks for all of the replies. I'm working two jobs right now so I haven't had a chance to check anything recently. After reading some other forums, I'm leaning towards the problem being somewhere in the front drivetrain assembly.

I'll update when I have a chance to do so more testing.

[Dougalass]

Well I have the same problem. 99 two door Tahoe, it starts after 60 mph and trails away after 70 mph. If I take my foot off the gas when going that speed it goes away. I also tried staying in third gear at 60 and the same vibration came back. Th U joints were replaced last December and I just bought new tires yesterday and the problem still exists. The vibration wasn't even there three weeks ago. I have to drive cross country here in a month and would like to have an idea what this problem is. Thanks,

[denialfans]

Update: I think I have ruled out the engine and transmission, because I tried changing gears manually at different speeds with no effect on the vibration. The other morning on my way to work, I looked at the speedometer and I was going 73 mph with only minor vibration. I tried to get it up to that range again today and the Tahoe felt like it was about to shake apart.

Hopefully I'll have more time in July to fix my vibration problem.

[mrstein69]

I'm having the same problem... 60 mph - 75 mph shake. I don't feel it in the steering wheel, but the entire body of the truck.

**** Has anyone found the answer to this problem ***

[andjh123]

I've found the problem in my case; the centering kit on this double cardan Spicer joint I have (front joint on the driveshaft/next to trans) goes out after a few thousand miles b/c it's next to impossible to lubricate with grease like you're supposed to.

For any who are unfamiliar with what I'm talking about here, it's basically two u-joints joined as a sort of single unit or joint via an "H" assy with a centering kit in between them--basically a spring and other parts that make sure both u-joints consistently share half of the total angle. When this spring breaks or other parts warp due to lack of grease, the amount of angle each u-joint is acounting for fluctuates constantly and results in heinous vibration. I have to use this type of joint b/c the lift I put on resulted in excessive driveline angle coming out of the transmission (the rear axle is shimmed up, so the angle back there is still close to stock) that will burn through normal u-joints in a flash.

Probably more than anyone cares to know, but my point is--from my understanding, everyone else here has vehicles at stock height with stock single u-joints that exhibit vibration problems almost identical to those that I experience due to this constantly failing joint, very interesting....

[mrstein69]

Well..

I took the rear drive shaft off to inspect the drive shaft U-joints. They look good and snug so I reinstalled.

I put the back of my truck up on jack stands, spun the rear tires up to 75 mph... smooth as butter.... so now I'm guessing something in the front. I've been told this vibration can occur from the front 1/2 shafts.

As I was taking a closer look to the front 1/2 shafts, I can see greese being spun out of the left side 1/2 shaft upper boot. So even thought all rubber boots are good on the front 1/2 shafts, I'm guessing I have a bad U-jont in the left and/or right 1/2 shafts. I plan to replace them next weekend. I'll keep everyone up to date on the out come.

[denialfans]

I wish I had some news to report, but I haven't had many opportunities to work on my Tahoe.

I was wondering if it's safe to remove the front driveshaft (transfer case to the front differential) to rule out the half shafts.

[mrstein69]

Originally Posted by denialfans

I was wondering if it's safe to remove the front driveshaft (transfer case to the front differential) to rule out the half shafts.

NO...NO... NO....

Do not remove the 1/2 shafts and drive the truck... Don't ask me how I know...but don't do it... your wheels will fall off..... NO JOKE !!!!!!! If you remove the front drive shaft, the 1/2 shafts will still turn since they are directly connect to the wheel.

As for the front driveshaft... I don't know if you can remove it safely or not.

[mrstein69]

Well, I replaced the 1/2 shafts, I still have the vibration. While doing to the 1/2 shafts I noticed the Pitman arm and Idler Arm were very loose. I'll be replacing them today.

[mrstein69]

After replacing the pitman and idler.... I still have the vibration.