I'm starting to detect a shake at around 70 mph. It's blatantly obvious by 75, and almost undriveable by low 80's.....which I haven't done since I found this problem.

The car feels fine up until 70. The tires were rebalanced just in case last weekend and all were within tolerances, except the right front which was 1.75 ounces off. All are now balanced and the problem didn't go away.

Unfortunately since it doesn't see much highway driving, there's been a L O T of work done since I last did any high speed cruising. New(used/rebuilt) tranny, new (used) driveshaft, new (used) 9-bolt, as well as all new steering linkage, STB, springs and shocks.

Someone suggested swapping front wheels off my S10 to see if it could be bent rim. I guess even a balanced front wheel can shake at highers speeds if it's bent.

....any suggestions? Things to check? I REALLY don't want to start throwing parts at this especially since the entire front end just got put back together.

 

Did you have the driveshaft balanced?

 

Driveshaft is what I'm thinking too (for the record)

....When I was doing the tranny swap at my buddy's house, we noticed that my original DS was really corroded and the UJs were a bit rough. He said he had one out of a parts car that was in much better condition. At the time I didn't think much of it since it was clearly in better shape.....

...but to answer your question, NO! I just assumed, and we all know what that does

What kind of shop do I call to have it done? And do you think it's really likely that the DS is my problem? Obviously you can't be sure, but is that common?

 

I had the same problem in a Honda civic when I hit 80 mph. I had an alightment job, and the problem was solved.

Bill

 

It's possible, the balance on the stock steel shafts wasn't that great to begin with. You'll need to take it to a driveline shop to get it balanced.

 

If your driveshaft and u joints check out ok, you might want to check out your torque converter too.

My 98 Tahoe would shake pretty bad at 65-75 mph, and it would shudder at 45 mph in OD with the TC locked. When I tapped on the brakes to unlock the TC at 45 mph the shuddering went away. My guess is the clutch lining was badly worn causing an imbalance at high speeds whether the TC was locked or not.

Long story short...a new TC cured all. You mentioned your tranny swap, did you get a new TC with it? It sounds like a long shot but I was going nuts for months trying to figure out my Tahoe's problem.

 

Yep, it came with the tranny. Not brand new, but less than 5000 miles.

...I'm hoping that's not the problem!

....but that's the right excuse for the T56

 

i have experienced where bad front rotors would cause higher speed shacking, aligment, tires, tire pressures, balanced tires/rims, driveshafts, u-joints

from the various types of vehicles thats what i came across

if i felt the shake in the seat of the pants/floor boards, turned out to be driveline related/broken mounts, worn mountsou run it in
if you run it in neutral at those speeds and it goes away, then thats where the problem lies.

if it was more in the steering wheel feel of the shake, turned out to be more front end related (alignment, suspension like tie rods, rotors, and of course dammm fix-a-flat in the tire)

geezzzzzz
i've expirienced all this, i am getting old LOL

ohhhh yeah
various makes and models too

and on my 79 TA
subframes helped some too......

 

Hi Chris...look into the driveshaft. I had the same vibration on my RS. I swapped to a LS1 aluminum shaft and it went away. That would be my first move.

Ed

 

Vibration problems I have had on my car

1. drive shaft, havn.t cut one open but I have been told that the factory one had a sound dampening material in it. it eventually comes loose and the drive shaft can't be ballanced very well. I had my drive shaft ballanced and a week later the problem came back, nasty vibration at higher speeds and it got worse when I let off the gas. I noticed that when I let the car sit a while it was worse. took the drive shaft out and stood it on end all winter once, no vibration problems for about 3 weeks. get a new drive shaft if you have these problems

2. warped rotors (done this a lot with my stock brakes) vibration gets worse when you step on the breaks

3. flat spotted tires, two causes 1. leaving the car parked all winter 2. locking up the brakes

4. tire wear problems / tire delamination in my case not getting it aligned after replacing the idler arm I wore the inside edge on a tire bad and it kinda bubbled you couldn't see it but you could feel it with your hands and definatly feel it at speed

hope this helps

Ryan

 

Sounds to me like thedriveshaft is 180 off on the rear....The driveshafts and the yoke on the rear were painted yellow on 1 side...if you put them 180 out of sync it will vibrate @ ~70

 

well if its not the driveshaft which it probably is... my car shook real bad at about 70mph + and i put it on the lift and my sway bar endlinks were almost totally gone... that might be your problem but i doubt it b/c if you have been under it that much looking for the problem then you would have noticed it b/c the endlinks are kinda obvious.

 

I'd say either driveshaft, bad tire or bad balance. The bad tire might have belt coming loose and some tire techs miss it if it's not too severe. Or the balance may need to be done within an 1/8 oz. instead of the usual 1/4 oz. This was a fix for my Neon that did the same thing at around 70-72.