My dalema is my dam rear diff mount it was broke. Replaced it with a used one (should have bought new ??? ) and had it installed and it broke in about 2 hours of driving. not that friendly of driving though. Anyone have this prob??? Or is there a heavy duty mount I can get somewhere???

Maybe your driveshaft bad? If driveshaft is off car, how easy do U-joint pieces move?

Its definitly the mount cause the rubber off the old one that connects to the diff was completely off fell off some where on the road, and the rest was still connected to the mounting part on the frame. The newer used one ( i didnt check yet) but think the rubber just tore off again. CRAPPY MOUNTS :madgo:

this is a common problem with Rx7s... I have the same problem right now and I have a couple of friends who have FCs that blew the mount as well... there are stronger mounts yes, a new one will work also, but eventually it will go as well (if it's the exact same as the stock one).... I haven't fixed mine yet, car hasn't been able to move, but tommorow I finish the haltech install and then i face the mount problem...I'll let you know what i do (not buying a stock one)....

try to get a new one from an 89 turbo thier quite strong from what I hear

All 86-91 differential mounts are the same. You can get stronger mounts from Mazdacomp. ANother option would be to make a mount out of angle iron.