I have a 2nd gen 87 turbo II. For some reason, the rear end has a bumping/knocking noise when I shift gears and tap the gass. I say tap the gas b/c when I do this every little time I hear the knocking noise or whatever in the rear end. Someone mentioned to me It may be the U joints or the differential mounts but when I checked these things nothing appeared to be wrong. So I was wondering if anyone else had this prob before or know what it maybe. If anything sooner or later Im going to take it to a shop. Thanks

 

yeah ... i would suspect the mounts first, too. how did you check them?

 

Well I put the rear end on jack stands and took a flashlight to all around the differential and the mounts and felt all around it for anything major like cracks or breaks and the mounts seems to be bolted in tightly also.

 

Check the fluid level in the differential. It may be the gears you hear. Also, the 2nd gen RX-7s (86-92) had a rear suspension that allowed the rear wheels to steer into turn. Sometimes the bushings in the suspension wear out and cause the car to feel like the rear is fishtailing a bit when you are going straight, and you may hear a knocking sound.

But I'm just shooting in the dark. Its hard to diagnose sound on the internet cause I can't hear it.

 

Jack the rear up again. Turn the car on, and gun it (I used a broom handle to push the gas) Look at the differential. If it obviously moves more than like a few millimeters, your front mount is shot. Not uncommom, but a BIOTCH to fix.

 

Thanks guys Ill check it out asap

 

AAAAAA HAAAAA! I believe I found the problem, As I was draining my oil today I figured Id look around the differential while the oil drained. I didnt think before to see if there was any play in the drive shaft or around the U joints. So when I checked it there was atleast 1/2 to 11/2 inche of play. I guess that my U joints are loose or something. But when I turned the Dshaft it would make the same noise that I would hear while driving the car. Now.......what do I do to fix it?