Ok ive been havin vibrations at 2500 rpms in 5th gear only. I just put new u joints in my driveshaft and had it balanced. It got a little better but vibration is still there. Also i have a tremec t-5 i believe. it came with the car. could this have anything to do with it? wat u guys think??

 

any suggestions at all guys?

 

check your motor mounts and tranny mounts. The 5th gear is a really tall gear on any mustang and really makes the engine work harder to move the car.

 

is it only at a certain mph? what happens if you stay the same speed that 2500rpm's in 5th is and go into 4th, does it go away? if you coast in neutral is it gone? if its only in 5th gear and goes away if in 4th or neutral, i would guess either a bad motor or trans mount, or something w/ the trans. make sure all your mount bolts are tight, also, make sure your exhaust isnt hitting anything, i ve seen that and you would swear its a vibration

 

the pinion shaft in your rearend could be loose causeing this that was the problem with mine !!!!!!!! the pinion need 30 inch pounds of tourqe to turn it! just sounds like you lost the preload!

 

but i would think you would feel the pinion prob in other gears, because its always spinning the same speed, if your going 55mph, it doesnt matter if your in 5th, 4th, neutral, its still spinning for 55mph

 

Check your tires for bumps or balance. They have a tendency to vibrate your car at a certain speed...which for you seems like 5th at 2500

 

+1 Could be tire cuppage

 

Some new shocks and a good burnout will fix that problem

 

if its a a certain rpm it could be a motor mount or any of your accesory pulleys