NASTY vibration over 100 mph?

[98SaleenSnake]

im getting a nasty vibration right when I hit 100 mph. I had the driveshaft balanced and I put different rims and tires and nothing helps. I cant figure it out im starting to think that my car is too low. any input would be great, car has always made this vibration since I can remember. maybe before I did the terminator swap too but I cant remember that far back.

 

[Blown_By_You]

im getting a nasty vibration right when I hit 100 mph. I had the driveshaft balanced and I put different rims and tires and nothing helps. I cant figure it out im starting to think that my car is too low. any input would be great, car has always made this vibration since I can remember. maybe before I did the terminator swap too but I cant remember that far back.

I've put my car up on 4 jackstands.. SECURELY, and driven it up to whatever speed I was having the vibration at to see what was out of balance.. turns out it was the axle, and it was very apparent.

 

[DVJ38]

Is it a bad vibration or more of a grinding type noise that vibrates? I ask because around that speed in 4th and 5th my car used to make a grinding noise and vibrate real bad. After a tranny rebuild all was good.

 

[Blackbox19]

In general, Can you tell where its coming from, rear, front or middle. that would help pin point the areas that cause vibrations.

Get this, a Rotor that gets a fin knocked out of it or a big iron rock wedged in will cause a vibration at the speed you going. Since you changed tires but did not say they were on another car that did not vibrate at 100. Cause at those speeds, a tiny bit out is going to cause issues. Even multiple sets of tires can be out just enough.
I have run well over 140 mph on circle track and when things get hairy we start with tires, then move to anything spinning and then to the things that hold those parts steady. Shocks will give up at certain speeds and not hold. brakes dragging also.

 

[98SaleenSnake]

It's hard to pin point but I'm thinking it's the rear end I had the trans rebuilt and drive shaft balanced. I'm thinking it's going to be the rear end housing when I bought the car I changed out all the rear end internals but the housing must be trashed.

 

[bumsoil]

had a vibration above 80, bad near 100. got front tires re balanced, problem solved.

 

[gardensnake281]

I know you said you have gotten your drive shaft re balanced but did they or did you replace your u joints i had the same problem after i put my 4:10s in ended up being worn u joints

 

[98SaleenSnake]

I know you said you have gotten your drive shaft re balanced but did they or did you replace your u joints i had the same problem after i put my 4:10s in ended up being worn u joints

yep brand new u joints on both ends.

 

[98SaleenSnake]

Little update, car is still making vibration from the rear at 90 to about 105 than decreases but as soon as I let off the gas it makes the worse vibration until about 80 than goes away.

So I'm guessing that the rear end bushings are toasted. I purchased all new rear suspension gear hoping it will solve the problem

 

[NVRL8TE]

Keep us updated.

 

[mustangsvt281]

my upper bushing on the differential housing was shot. I replaced it, have yet to give it a try yet though. Car is waiting on trans parts to come in.

 

[98SaleenSnake]

Vibration still there! Wtf it's driving me crazy. Can't figure it out. I'm almost positive that is has to do with the pinion angle. Maybe some adjustable uppers will help?

 

[bumsoil]

Get wheels balanced. A used tire place will do it for cheap.

 

[98SaleenSnake]

I did that already. Even with new rims and tires.

 

[LilBerx]

Curious, I have the same issue.

 

[Weather Man]

Try this, you lowered your car and may have upset the pinion relationship.

http://www.hotrodhotline.com/md/html/drive_shaft_harmonics.php

Good luck man.

 

[98SaleenSnake]

Try this, you lowered your car and may have upset the pinion relationship.

http://www.hotrodhotline.com/md/html/drive_shaft_harmonics.php

Good luck man.

Very interesting thanks for the link

 

[Ruslow]

I would be looking at your driveshaft angles.Bet that is your problem.If you lowered the vehicle you changed the angles and if you get the vibration worse when you let off that is pointing to the pinion angle.have them checked and I bet they are not even close.Stan

 

[03SonicSVT]

OP, did you figure it out? I have a vibration in the rear above 100mph. I think its my diff and or irs bushings. I am going to replace them anyways since they are shot and see if that fixes it.

 

[OW99]

I would be looking at your driveshaft angles.Bet that is your problem.If you lowered the vehicle you changed the angles and if you get the vibration worse when you let off that is pointing to the pinion angle.have them checked and I bet they are not even close.Stan

+1 exactly what I was thinking.