On my 95 Gt, when I am driving around 90 on the interstate and put my clutch in, I get a weird vibration like it is going to shake apart underneath. It is only at high speeds so it seems to me it would be driveline related. When I shift at high rpm's it doesnt do it, only with high speeds. I have a new King Cobra clutch in the car, I dont think it is even related to the clutch. I have 3:73 rearend and the stock T-5 Tranny. Any suggestions?

Chris

I would check the U-Joints first. Then (if you haven't already) remove the dogbone from underneath the rear axle. The dogbone is a balancer for the factory gears, and is not necessary when you install aftermarket gears. This might work. Also, where do you notice the vibration. If you can feel it in the seats, it is in the rear portion of the car. If you can feel it in the steering wheel, it is in the front half.

The driveshaft could be out of balance. Many times when a driveshaft is removed, people forget to mark on the u-joints where the drive shaft orginally sat. It is important to put it back, the same way it came out.

I would suggest moving the driveshaft a slot over on the u-joints to see if this helps. then move it another slot if needed.

Not to disagree, but I have heard of problems if you remove the dogbone.

If I recall, scott here at V8Mustangs did that and ended up putting it back on. It might have been someone else.

I could be wrong about this, but I have always left mine on with no problems.

I think you may be right Glen, I did recently have the tranny removed, so the mechanic may not have put the driveshaft back in correctly. If I were to get an aluminum driveshaft, how would I know how to put it in balanced? Why I ask this is becuase I have one ready to put in, just havent had time to do it.
Thanks
Chris

Actually guys when I had my 3:55 gears, aluminum driveshaft and 31 spline axles installed, we left the dogbone or as some would say mooseballs, off the car. After the install I noticed a vibration in the driveline around 80 mph and up. Rechecked the install and everything looked fine. Ended up reinstalling the mooseballs and the vibration disappeared.

Hope this helps,

Crashz28:

The aluminum drive shaft should be balanced already. Installing it is not as critical as the factory driveshaft since it is aluminum, it is much lighter. therefore much less weight/mass spinning and as a result, not a balance problem.

The big benefit of an aluminum driveshaft is less weight. It takes less power to get it spinning, which help response times. Kind of like the aluminum flywheel that came on the 94-95 Cobra's. Less weight to get moving the better, plus less balancing to worry about. Plus, less vibration on the main bairings of the crankshaft.

The are driveshaft/spring shops that will balance them for you if it becomes to much of a problem. Look under truck parts and equipment in the yellow pages to find a place.

One last thing for someone to consider if unlike you, they don't have an aluminum driveshaft to put in. Ford welded weights onto the driveshaft when it was balanced at the factory. Sometimes these come off.

Hope this helps