Hello, I'm new to this community and just bought a 79 RX7 with a five speed. I've noticed that there is a grinding noise coming from my transmission when in fifth gear. It's not too loud, but it's enough that it concerns me. I just wanted to know if there's anything I can do about it.

 

Other than a rebuild, you can try replacing the fluid. If you do, remove the fill plug first before the drain plug. This way if the fill plug has an issue, you can still drive the car.

 

So "grinding" like when put IN to gear? Or steady whine/grind while IN gear? One could be weak syncros, the other, just old age
My SA has a notable whine in top 3 gears, but at 107K mi am putting this off to old age, plus general road noise covers it up. Mostly.
I have run sync oil in TX and diff for decades. Shifts flawlessly.
Whereas if the crunch comes going IN to gear, that is a diff matter, tho again one that 'might' be mitigated a bit with synth oil...

Stu A
80GS
AZ

 

It doesn't grind going into 5th. Its just a steady grind/whine. I'll check the fluid when I get a chance. Thank you for your help