Hi everyone, this is my first post with my first rx7. It’s a 83 model year GSL. I am making this post today because I am having a drive train vibration issue that I can’t seem to diagnose. I’ll start by listing the issue. So what I am having is a fairly violent left to right shaking of the drive train ( I can feel and see the shifter shake) during pull offs when starting from a stand still. From my tests, I have concluded that it only happens in first gear and only when multiple pull offs are performed. What I mean by that is the first 5-10 pull offs are smooth with no shaking. After that the vibration starts to slowly build. The vibration is right at the top of the clutch let off. If I stop using first and use second gear the operation is smooth. I can use second all day with no vibration. If I switch back to first (given enough time) the process will start over and I will have another 5-10 operations before the vibration comes back. To me this would indicate a heat related issue with first gear.
I have checked the engine and trans mounts as well as the u- joints All seem to be good. The car has a new drive shaft because I thought the u-joint was the problem. My next option is to replace the clutch and pressure plate. I can’t see that being an issue since second gear works fine for pull offs and I have no other shifting issue. Maybe someone has had this issue or could explain to me why this could still be a clutch.

Also, I have tried to search for a similar issue on this site. I haven’t found anything that aligns with the problem I am having.


Thank you for your time,
JGOFF

 

Sorry to know of your troubles.
​​​​​​Perhaps this will help:
https://www.rx7club.com/1st-generati...-only-1130142/

 

Thank you! I’ll check that out! The next step is definitely a new clutch and resurfaced flywheel. Hopefully that fixes the issue. Thank you for your time!

 

Check the motor and trans mounts. You'll need to put a floor jack under the trans and remove the trans cross member to check the trans mount. Same goes for the engine mounts. You'll need to use engine hoist or wood/jack to hold ther engine enough to remove the engine mount to bolt (each side) so the pressure is off the mounts. What happens is that the rubber separates.

 

I have checked the mounts for both he engine and the trans. However, I didn’t do the method you suggested. I’ll give that a try as well. I plan on replacing the trans mount while the trans is out for the clutch. I’ll make sure to do a more details inspection of the engine mounts while I’m at it. Just moved to SOCal and I am still working on securing a place to do the work. The apartment doesn’t take kindly to cars on jacks haha. I’m currently installing an alarm and power locks in my parking spot and that I feel is pushing my luck. Thank you for your advice!