Vibration at 3,000rpm and up

[Iceman95]

I just bought a 1999 Grand Prix GTP about two weeks ago that has a rebuilt transmission and i've noticed at highway speeds when I give it just a little gas and get it up around 3,000 rpm and above it seems to vibrate just a little.. Engine or tranny vibration? I have no clue.. haha

[brandonl2000]

could be cv axles, could be motor mounts. you check any of these things? tires?

[Shiftingshaddow]

its probably all three

[Iceman95]

lol lets home its not all three.. I know its not the tires. I'll check the mounts tomorrow.. that makes the most sense to me.

[Scottydoggs]

and just how do you know its not the tires? ive had tires of my own cause vibrations at only certain speeds. and others here have also hunted for a this, that or anything, and it turned out to be the tires.

its best to rotate your tires from the front to the back, if it goes away, its the tires. still there, now you know its a mount or a axle.

[Iceman95]

Well I didn't figure it was the tires because I don't really feel any vibration in the steering wheel. I'll probably check the tires anyway though.

[98L36]

+1 for considering tires. I had that issue for a while, would only do it at like 40-45 or something like that. Switching front/back seemed to help (and I've got directionals so I really mean front/back switching, not left/right and front/back)

[Scottydoggs]

i try not to swap rights to left, as ive seen belts buckle from it back in the day. i like them to spin one way from day one that i own them.

ive as well as others have also had tires balance ok, but not be ok on the car.