Vibration from 30 to 40mph

[jpaitala]

My suburban just started doing this...
Does not matter if I accelerate slowly or fast it happens between 30 and 40mph.
And if I let my foot of the pedal when it vibrates the vibration goes away...

Any ideas?

Thanks.

[jpaitala]

Anyone?

[Cowracer]

In order of probable cause:

Wheel out of balance
Bad tire
worn shocks
Worn front suspension (ball joints, tie rods, etc)
Steering box adjusted too loose

TIm

[Hye]

U-Joints, if everything in Tim's list checks OK.

[wayne zylik]

If the vibration is in the steering wheel check out the front end if you can feel it in the your seat then it is the rear drive train components

[jpaitala]

Got the tires re-balanced yesterday...no help whatsoever. U-joints are ok, just checked.

Tie-rod ends and ball joints are not the best ones but there's no excessive play on those.

Steering wheel shakes a bit but not too much, it's most visible on the dash board when it vibrates.

On another board someone suggested that could be brake drums that are done and that could cause vibration.

This started last week after I had the truck washed at a local detailer and he washed the underside of the truck also. There was no time to let it dry, so I had to drive the truck right after the wash and it's freezing here. So could it be just "frozen" ??

[Barry Nave]

That could do it if ice formed on the drive Comp's. Throwing drive train out of Bal.

[mrussell]

I had the exact same problem. I thought that the ujoints were ok. No movement whatsoever when under the truck checking (multiple times). Different story though when on the lift. Smoother than ever now

[jpaitala]

Originally posted by mrussell:
I had the exact same problem. I thought that the ujoints were ok. No movement whatsoever when under the truck checking (multiple times). Different story though when on the lift. Smoother than ever now So you checked the U-joints at the driveshaft by hand and there was no play. But when you lifted the truck and did a recheck there was visible play on the U-joints?

If so, I think I must try that also.

[jpaitala]

?

[moondoggie]

Good Day!

Because your problem happened immediately after washing the underside, the 1st thing I'd do is park it in a heated garage overnight & see if the problem goes away (ice melted off whatever it threw off-balance).

U-joints? I've had them where they were absolutely without any relative motion on the driveway & after I'd put the vehicle on stands. After pulling the driveshaft & then the u-joint out, I found one or more ends completely dry. Replaced u-joint - vibration gone. This has happened more than once over the years.

Trust the others to determine if it's drivetrain, steering, or whatever. I'm a poor mechanic & can never get the troubleshooting thing right. But, once I did go for the u-joints (on other folks advice or dumb luck), that's what I've had happen a couple times.

Blessings!

Brian Johnson, #5044

[autocrosser]

If you had the tires balanced after it started they may have balance them with some dirt or ice on the back side of the wheels so the problem would come right back if the ice melted or the dirt got washed off.

Have you checked for separating tread on the tires?

If it worked ok before the washing it probably isn't a worn component like a u joint.

[Scooby]

I'd look at the tires real close. I have had many tires do what I call "break a Cord. It will develop a lump, and will drive like a tire out of balance. The tires will still balance, but with weight on, it will be lumpy. Try rotating tires and see if the vibration changes at all.

[jpaitala]

This may sound real stupid but.... I was re-checking the U-joints at the rear driveshaft yesterday evening with the rear end of the ground. I thought that I will remove the driveshaft just to be 1001% sure about the U-joints, so I removed the small "U-bolts" that hold the driveshaft to the rear end, but the driveshaft would not move. I have removed/installed several rear driveshafts myself but never seen it like this. It was like welded in there, it just would not come out.

Is there some special techinique on the suburban to do it or...?

[Dezman125]

Hi
you need to get a bar inbetween the ujoint and the diff and pop it away from the diff. Sometimes they fit real tight and a little road salt will hold them tight.

[jpaitala]

The U-joint at the end of transfer case was a total wreck. As soon as I got the driveshaft off from the transfer case I knew what caused the vibration.

Thank you for everyone who helped me with this one!!!

[jpaitala]

A short Quicktime video clip off the "broken" U-Joint: The Video Clip (http://www.juhapekka.com/auto/U_joint.mp4)