well, since the day i have owned this GTUs, it has had a wicked bad thump from the rear whenever i get on or off the gas (decel, accel, shifting, etc). and there is seems to be an assload of driveline play. if im coasting down in gear, between 3000 and idle, the car will buck VIOLENTLY and i can envision the pinion flopping up and down like crazy.

the car has new motor mounts and the tranny mount is intact when i checked during the last oil change.

sooo, what do you guys think the best course of action would be?

New stock Front Diff mount with Pinion snubber?

Remove existing Front Diff mount and weld solidly?

Same as above, and add Pinion snubber?

Same as above and replace rear diff mounts despite no apparant issues w/ them?

i havent been messing w/ RX7's much at all... ive been working on Supras nonstop. on Supras, the rear diff is FIRMLY affixed to the rear subframe with 2 12mm bolts up front and 4 12mm studs in the rear.


what was mazda's big deal with insisting on mounting the rear diff w/ rubber bushings? what would be so detrimental about solidly mounting it to the FC's subframe? I mean, i know my supra is superiour to the RX7 but how bout i solidly mount the rear end to the subframe... has anyone had something else break in the rear subframe assy due to using solid front and rear diff mounts?

If I change the front diff mount to a fully welded unit, will taht circumvent the need for a Pinion snubber?

any thoughts or experiences with these potential solutions?

thanks
chris

 

The rubber mounts have been known to be capable of holding down whatever power is thrown at them, problem is they are 15-20 years old

Rubber degrades over time.

A brand new stock mount will last you for as long as you own the car.

There aren't any real proven side effects of a solid mount other than increased vibration.

 

sweet. if i get the solid front diff mount, i should be able to get away without needing a pinion snubber. id rather have a solid mount. it cant see how itd be more vibration than my supra, and thats mounted 100% solidly to the subframe.

i just saw one on Ebay for $65... seems a little steep for a stock mount, metal and some weldery. oh well.... i guess ill see.

 

sure its the diff mount? could be a bad u-joint in the driveline.

 

who sais a new bushing will last the lifetime of the car? you own a turbo?


mine was replaced prior to me buying my car, it has now torn 3/4 of the way through... the car has only had 8k miles put on it..

 

If you drag race alot and beat the absolute snot out of your drivetrain, sure, it could break.

I've owned many RX7's young grashopper.

 

^ What he says is true, they should hold up fine in most cases but i've broken 2 of the stock rubber mounts and 1 welded mount that i made myself (not enough penitration on the weld). I drag race/auto-x/ and play around with my car all the time so i know things will break.