Hey, I've got a problem with my RX7 (1989 auto, vert.)...it is shaking and vibrating whenever I let off of the gas, and now, it is beginning to shake and vibrate when I drive. I think that it's in my differential. Anyone confirm this?
And secondly:
I have an 86 base parts car with a manual tranny...I was wondering if I could switch out the differential, and if it would work and not shake...I know that they are geared differently, and that my 89 is limited slip, whereas the 86 is not. Is this possible? Anyone have any help to give a brother in need?

Thanks in advance!
Grace & Peace,
Matt

 

There won't be a problem in changing the diffs, except that the speedo will be off (that's not a big deal though, right). First check to make sure everything is bolted down properly (diff, trans, engine, driveshaft).

 

driveshaft universals are bad...

 

True. To check them out crawl underneath the car and push up and down on the drive shaft. If there is play the u-joints are bad, if there is no play then they are good. If they are bad Mazda only sells the drive shaft with the u-joints pressed in them. Mazda doesnt sell the u-joints seperately. I dont know if you can get the u-joints seperately from an auto parts store.

If you swap rears from a manual to or from an automatic the gear ratios are different. I *think* autos have a 3.90 gear and manuals have a 4.10 gear.

 

so, does that mean that I won't have any problems with them bolting up with the older parts car having 4 lugs and being a series 4 with a manual, and mine being a s5 with 5 lug wheels? I just wanted to verify...thanks y'all!
Grace and Peace,
<>< Matt ><>

 

check to see if your engine and trans. mounts are still good they might be broken replace them if needed

 

Make sure your lugnuts are tight. Won't hurt to check. My first guess would be the driveline though.

Frank