slips out of 3rd gear
 

Hoping for some diagnostic help...

I had my 1999 Spec Boxster (90k miles) at the track last weekend. Part way through the day, the manual transmission started slipping out of 3rd gear. All other gears work fine. I could shift into 3rd ok, but it would slip out of 3rd when I let off the gas or went over a bump.

I tried adusting the linkage at the shifter to bias the shifter more toward 3rd, but that didn't help.

I jacked the car up and manually worked the linkage at the transmission while manually turning the wheels, and was able to reproduce the slipping out of 3rd.

Any ideas what the problem is or how to diagnose it better without dropping the tranny? Since all other gears work fine, the clutch seems fine.

Thanks, dave

Don't kill the messenger. You need a rebuild.