GimpyHSHS

Alright. Thanks man. Really appreciate it.

Roadmister

I have a minor drive train vibration that is eluding every fix I have tried. New: Tires High Speed balanced, U-joints, Driver side mount, Transmission Mount, Alignment. I am starting to wonder if it is just a characteristic of the vehicle? It seems I can make it happen when slowing down from 50mph to 40mph. Lower speed it goes away. At 70 & up it runs smooth.
Ready to change both L & R motor mounts & Trany mount with Polyurethane ones. In reading this post I saw a question on the Poly & Solid mounts?? Any issue I should be aware of?

dawson1112

I doubt your issue is mounting related. More likely in the rear differential. I am wondering if this vibration is accompanied by a whine? Check your pinion for movement by pushing the drive shaft up/down left/right and see if you can move the pinion flange around. Improperly installed pinion bearings , or wear can cause vibration, especially when slowing down or accelerating hard. Also it would be a good idea to check wheel bearings for play, and carrier bearings for wear.

My 90 fox had vibrations in the rear due to a faulty install of the pinion. I had to pull it all apart reinstall new bearings and crush collar, then set bearing preload to spec. This vibration was quickly identified by checking for play at the pinion flange.

84CopperGT

Could the driveshaft be out of balance?

GimpyHSHS

So sorry about the lack of an update! Last Saturday I put another bellhousing in. It had a veeery slight crack in it, but I got it welded up. I pulled the DS and U Joints all out of a mustang on the salvage yard my car lot owns, and it turned out to be an aluminum DS. I put it in and the car runs straight and true. So it was DS or U Joints. I really regret not putting this one in before I cracked the second bellhousing. Appreciate the help guys!
Im proud of myself too. Ive only gone 123mph in it since I fixed it!

84CopperGT

Nice. I really want a new DS but mine only vibrates above 100.....like the rest of the car.

dawson1112

well Im glad you got it fixed, too bad you had to ruin 2 bell housings in the process when the answer was given in the first response to you. lol

GimpyHSHS

True. We all learn our lessons! Bet your bottom dollar it won't happen to me again!

Roadmister

Thanks for the tips. No play in the rear end. Pulling the shaft to have it checked out. will update.

azdriveshaft

pull your shaft out and ship it to us at Arizona driveshaft. We specialize in Mustang and high performance shafts.

If we can help you in any way feel free to call us at 480-898-1957