1bad03snake

iTrader: (16)

I have a 99 mustang with aje k member and cross member with upr solid rear bushings. I had the tires balanced yesterday and are good to go. My problem is at 50MPM my car starts to vibrate you feel it in the seat and the faster you go the worse it gets. If you let off the vibrations come and go until you get below 50ish MPH any idea's?? I have the pinion angle set to -1 and the drive shaft is new.

Matt

wssix99

iTrader: (5)

Do the vibrations go away if you go faster, like 60 or 70? If so, you got a bad balance job.

1bad03snake

iTrader: (16)

I havent tried to go much faster i didnt want to break anything I will go for a drive tonight

DW SD

Can you put the rear axle on jack stands and spin up? Then you could determine if driveshaft or rear tires (you could also remove rear tires) to isolate.

Do load the axle so you can approximate operating driveshaft angles. You might want to post output shaft (vs. ground), driveshaft angle (vs. ground) and input pinion angles, too. -1 doesn't help much without the others.

wssix99

iTrader: (5)

If this first appeared after having new wheels put on or balanced, odds are that's where the issue is. Very frustrating that this can happen after a "precision super robotic/can't mess it up" balance job.

truckdoug

iTrader: (25)

as long as there's a person putting the weights on the wheel it can and will get f'd up. it's happened so many times to me I lost count. Stopped going to big chain tire places.

I finally found a good tire and alignment guy and I am grateful.

1bad03snake

iTrader: (16)

I found the transmission cross member (AJE) for some reason is sitting low. I shimmed it up to get the tail shaft angle up from a -8. I need to move a few parts around to get any more angle out of it

Project GatTagO

iTrader: (7)

Keep us posted. It sounds like a driveline issue to me.

Andrew