I have been dealing with this for a while, but now its just getting annoying. While driving at higher speeds, the car get shaky. I take it out of gear and coast and the slower i go the it started to vibrate slower and slower... But i guess the point of that is that its not the engine shaking.
So what could it be thats causing the shaking? Because i have had the tires balanced twice and the car aligned a week ago. It still insists on vibrating! So what else should i check? Driveline, is this a typical culprit? And how do i go about getting this balanced?

Bubba

Sounds like tires, find a shop that has a Hunter DSP machine and have them balance your tires. This machine will actually measure tire runout and wheel runout so the 2 can be match mounted. I have seen many brand new tires get thrown in the scrap pile for excessive runout that caused vibrations you couldn't balance out.

You may also want to check into driveshaft, bent axles, warped rotors or drums, bent rims, incorrect tranny yokes, things like that. I had an incorrect yoke cause my 70 to vibrate at any speed over 60.

If you feel it in the steering wheel its the front end,if you feel it in the floor or seat its the rear end.

Here's the trouble, it could be anything! Oh, lets say tranny mount, or one of the enigne mounts. Not possible? it is. Vibrations are a royal pita since they can come from many places.

I'd check the driveshaft first. ( after tires/rims) Hopefully it a new UJoint from being smooth. Wierd harmonics can also set up for any of the rear bushings are shot.

I have a rim runout issue. Impossible to balance away. bad at 55-60, not so bad at 70. ASSUMING rim runouts have an ocillation frequency like tire balance, then I'd think infer in your case that its not that. Its direct, doesnt go away and it rpm related.

Driveshaft/tranny mount would be my first stop. And it might be many before you get it ironed out. Patience!