The transmission.

 

For jsut over 1k miles now its been in there. THe 4th gear syncro was weak...now all 5 gears are smooth as butter in shifting. 30 mph into 1st gear? no problem. Nice crisp smooth shifts.

 

Im wondering how long it takes before something breaks now....

so should I perhaps try this in my wagon's RX trans if all the gears are generally sticky and the reverse grinds?

Reverse has no syncro...so it will grind if the trans internals are moving. I would try adjusting the clutch cable some....