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Need help. BAD VIBRATION

6K views 11 replies 8 participants last post by  albrjmnz 
#1 ·
I'm hoping that someone can shed some light on a very bad vibration that my Cobra has developed.
It starts about 2700 rpm in 5th. (or about 4500 in 4th) and gets worse as you gain MPH or RPM's. If you shove in the clutch, the vibration gets worse. If you shift into neutral the vib. gets worst.
The vibration is so bad at 3000 in 5th, it's like sitting on a vibrator. The vibration sounds like a phasing vibration until you get up to 3000 then it's just bad.
Here's what I've done to date. Installed the following items
Pilot Bearing
Throw out bearing
Turned Fly wheel
Installed a loaner tranny
New universals, straighten and balanced drive line
new axels with bearings
replaced all bearings in 3rd member, 4:10's look good.
New tires, even installed my brothers wheels & tires but the vibration does not improve.

I'm wondering if maybe I have a bad pinion angle, or need to replace any rear bushing?

The car has the following. 5.0 supercharged, 90mm mass air. 30 # injectors, Mac equal length headers, 3" off road H-pipe,3" cat-backs, F-303 cam, APE Chip, Smog pump eliminator, Center force dual friction clutch & pressure plate, T-5 tranny, stock driveline, 4:10 gears, Eiback lowering springs, sub-frame connectors welded in place, lifting rails welded into place. '98 Cobra rims, 275/45 ZR17 Dulop tires about 1000 miles on tires.

Any help would be great.
SSSNAKE
:err: :err:
 
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#2 ·
Have you tried indexing the drive shaft? Loosen and turn it 45 degrees. Try it out. If that doesn't work, try 90 degrees and keep going until you find the best position. It's also possible you have a bad tire or rim.

Cheers,
Robert
 
#4 ·
i have had this problem with my other car. Although your car might be newer but this what i had to do. Everytime i would just lauch the car would viberate as you say and the exhaust pups when you drive. I later found out that my torque converter went bad and was not flowing fluid freely. You might want to check that or even take it to the dealer to get a diagonstic test to help you find your problem. Sorry for not helping much bu that is what happened to me. Well man good luck

99 cobra
 
#5 ·
Well If it still viberates with the motor disingauged but the clutch or as you said in neutral then its got to be in the drive train. It could be a warped rotor.All it takes is some one to use a air impact wrench and dosen't bolt the wheels in a bolt pattern it'l do in a heart beat.
 
#11 ·
99 Cobra said:
i have had this problem with my other car. Although your car might be newer but this what i had to do. Everytime i would just lauch the car would viberate as you say and the exhaust pups when you drive. I later found out that my torque converter went bad and was not flowing fluid freely. You might want to check that or even take it to the dealer to get a diagonstic test to help you find your problem. Sorry for not helping much bu that is what happened to me. Well man good luck

99 cobra
Cobras ain't got no stinkin' torque converters!
 
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