Anyone with a PST Aluminum Driveshaft?

[wals9331]

I have been having a vibration with my car ever since I put gears, diff bushings, and an aluminum driveshaft in it. I've set my pinion angle the best I can, but i still have the vibe. I am now questioning the driveshaft. My PST driveshaft does NOT look like it has ever been balanced (no weights on it). Anyone have a PST driveshaft and know if they come balanced or not? Thanks -Dan

 

[1999marg]

I can't imagine the PST is not balanced to perfection. Since you already adjusted your IRS's pumpkins input angle (so it is equal but opposite to your transmissions output shaft, then check the run-out on your IRS input and transmission output shafts. It only takes a few thousandths to make you feel it in your seat.

It is not obvious stuff like bent rim, flat spotted or worn tires. Does it occur at a specific RPM or gear? only under load? Vibration gremlins are tough. But not impossible. The 410's are a hoot once you get the vibration issue under control.

 

[wals9331]

Nah, its nothing obvious. Right now it happens at around 100mph....it was happening at 80mph but adjusting the diff angle seemed to help.

Where do you put the dial indicator when you are checking for runout. I cant seem to find a nice machined area. Thanks -Dan

 

[1999marg]

Dan

Take a look at this article they experience the same problem you had. It includes a photo showing them mounting the front dial indicator to the machined pinion on the transmission tailhousing output yoke. As for the pinion try the pinion flange.

2003 Ford Mustang Cobra Maximum Motorsports IRS Vibration Reduction Kit - Mustang Monthly

The theory is sound add washers 180 degrees from the point of max runout.

I have not tied this on an IRS Cobra but you could simply add a hose clamp to the driveshaft. If you feel the vibration in the shifter I would add it to the front of the driveshaft. If it is coming from the rear of the car place it on the shaft next to the differential. You could forget the dial indicators and just do a little trial and error. If the vibration is worse just move (slide the clamp around the driveshaft 90 degrees clockwise. If the vibration gets better try 15 degrees CW and then CCW. It is trial and error. Hope this helps.

Cheers