So i just bought an 88 rx7 n/a with about 78k miles.

everything is great, except for the fact that third gear grinds sometimes. only when im really revving and going fast does this happen. if i ease into 3rd gear and
shift slow its not a problem. but it sucks when i actually really have to punch it
(i.e. merging into fast traffic). i'm not the most mechanically knowledgable person
in the world. would anyone know the possible cause of this? and is the repair going to be serious and invasive? thanks

-pope

 

Syncro is starting to fail. Try replacing you gear oil with a good quality GL-4 (not GL-5) gear oil such as Redline MT-90.

 

Haven't tried the GL-4, but one thing we do with the 1st gens is run a 50/50 mix of gear lube and ATF. The detergents in the ATF clean the gunk out of the synchros in no time at all, and you can run this mixture full time.

 

thanks guys!

what do you think the odds are that i may need to have the tranny rebuilt or repaired?
i would really much rather replace the fluids.

 

Chances are good that the tranny needs freshening. It's usually the 2nd gear synchros that show wear first on the FC and older version rotarys. Along with what Kentetsu suggests, make sure the both the master and slave hydraulic are tiptop, the clutch hose is sound, and the clutch fork/bearing are well lubed. The pivot ball that the fork rides on has been known to fail/snap.The following links are to the online FSMs, carb manuals and other rotaty related reading.

http://foxed.ca/foxed/index.php?page=rx7manual

http://www.wankel.net/~krwright/cars/rx7/manuals.html

 

thanks much fellas,
gonna go get her checked out tommorow.