General Maintenance & Repairs Leaks | Squeaks | Clunks | Rattles | Grinds

Bad vibration at high speed?

Thread Tools
 
Search this Thread
 
Old 04-14-2007, 02:00 AM
  #1  
Launching!
Thread Starter
iTrader: (2)
 
TheSecretFormula's Avatar
 
Join Date: Feb 2007
Location: S. Florida
Posts: 254
Likes: 0
Received 0 Likes on 0 Posts
Default Bad vibration at high speed?

Since I got my Formula it has had a vibration at high speed. Once you get up past 85-90mph the whole car starts to shake. I got the wheels balanced and still had the same thing. Thought it might be a bad axle or carrier bearing. Rebuilt the whole rear down to new differential and axle shafts. Same thing. Thought I had a couple of bent rims. Changed the wheels and tires. Same thing. Any thoughts. Shocks, wheel bearing, tranny or motor mounts? It's weird because the car is solid as a rock until you get over 85 or so. It also feels like the engine might be breaking up and causing it sometimes. Maybe a bad harmonic balancer or something? It has new plugs, wires, fuel filter, air filter, etc. Any thoughs would be appreciated. Thanks.

Last edited by TheSecretFormula; 04-14-2007 at 02:28 AM.
Old 04-14-2007, 04:17 AM
  #2  
11 Second Club
iTrader: (30)
 
EDS01SS's Avatar
 
Join Date: Jul 2003
Location: Hampton Virginia
Posts: 1,049
Likes: 0
Received 8 Likes on 7 Posts

Default

Are you using a Polyurethane transmission mount? if so they have been known to cause bad vibrations. Also check your u-joints and your complete driveshaft for dings and missing weights.
Old 04-14-2007, 04:45 AM
  #3  
10 Second Club
iTrader: (5)
 
SpaZMaN's Avatar
 
Join Date: Jun 2006
Location: Chi-Town
Posts: 1,373
Likes: 0
Received 1 Like on 1 Post
Default

it should be something drivetrain related, i'd check your driveshaft, maby go get it tested.
Old 04-14-2007, 05:54 AM
  #4  
TECH Veteran
iTrader: (5)
 
GEARHED's Avatar
 
Join Date: Jun 2004
Posts: 4,397
Likes: 0
Received 0 Likes on 0 Posts

Default

As mentioned, check the poly mounts and shaft. If you have an older converter it may also (along with the ds) be going out and can cause a strange vibration, didn't check your mod list. Can you describe about where it seems to come from? (under the shifter, right front, directly under the hood, passenger seats)
Old 04-14-2007, 11:50 AM
  #5  
Launching!
Thread Starter
iTrader: (2)
 
TheSecretFormula's Avatar
 
Join Date: Feb 2007
Location: S. Florida
Posts: 254
Likes: 0
Received 0 Likes on 0 Posts
Default

The driveshaft looks fine visually. Actually it looks brand new which could be the problem in itself if it was not balanced correctly. It has no dents, dings and the weights are there. The U joints seem okay as well. The car has the stock tranny mount and is an M6 so no convertor to worry about.
Old 04-14-2007, 04:13 PM
  #6  
Launching!
 
Switchblade's Avatar
 
Join Date: Jun 2005
Location: Windsor, Ont
Posts: 236
Likes: 0
Received 1 Like on 1 Post

Default

You might want to double check your pinion angle. It should be at -2 or -3 degrees.
Old 04-14-2007, 04:22 PM
  #7  
Teching In
 
anniversary30's Avatar
 
Join Date: Apr 2007
Posts: 6
Likes: 0
Received 0 Likes on 0 Posts
Default

It was on the old lt1 cars but there was a recall on the driveshafts years ago. I only mention it cause my 96 ws6 formula had the same problem at 85 to 90. the whole dash would start to shake.
Old 04-14-2007, 08:23 PM
  #8  
Banned
 
qwkta98's Avatar
 
Join Date: Apr 2007
Location: addison IL 60101
Posts: 64
Likes: 0
Received 0 Likes on 0 Posts
Default

drive shaft might be outta balence




All times are GMT -5. The time now is 06:47 PM.