ive ben driving my car lately and i just got my tranny mount fixed(thanks injuneer on the heads up)but lately ive ben getting alot of vibration out of the car. the car drives and performs just fine, but soon as i get around 60 or so i start getting the vibration. i drove it last night on the highway and it was doing it so i wanted to see if it went away at higher speeds. i got up to 100 and it was really bad. it used to never have any vibrations at all. i would get up to 130(yea i know kinda wreckless)and it still wouldnt do it. what could it be now???

 

Are you running the stock steel driveshaft? Not unusual for them to cause vibrations with the swap to higher numerical rear axle ratios. You may just be noticing it more if you used a polyurethane tranny mount like the Energy Suspension.

 

Some things to look at
1. Tire preasure correct and even all the way around
2. Tire balance
3. Sometimes a tire gets out of round
4. U Joints.

 

the tranny mount never got replaced. it was a bolt missing and the one bolt that was in there was crooked. but yes its still stock driveshaft. it always kinda wobbled but it was so unnoticible i never really payed much attention to it. but now itout there like a sore thumb. but i was told it could be the wheel hub.i have hit a couple curbs but nothing damageed, just scratched my y pipe a lil. but i havnt gotton my tires checked or anything of that sort.

 

Need to start checking the tire and wheels, may have just lost a wheel weight.
One thing you can do that doesn't cost anything, is jack up the rear, support the axle with jack stands, remove the wheels and run the speedo up to 60 or 80mph if it doesn't vibrate it's probably the wheels/tires.