Transmission question: vibration in 3rd gear

[darcher]

Transmission question: Third gear vibrates.
I have a 1985 Carrera w/ the 915 transaxle and about 90K on it and the transmission has gradually developed a vibration in third gear that you can feel in the shifter. It drives fine, no clutch or shifting issues or noise. 4th gear is OK. The clutch is about 10K old and the trans was out for a first gear rebuild and resealed at 75K. If I push the lever forward about 1/4 inch you can't feel the vibration, so I have been driving it leaving my hand on the shifter as I get to 5th gear and all's well. But am I looking at an impending transmission problem that I should attend to right away? or can I drive it until it gets worse? This is a sunny Sunday cruiser that only sees 2-3K/ year but we want to take it on Porsche Club events in Omaha so reliability is an issue.

[timmy2]

How old are your shift coupler bushings? Also the shifter ball and cup as well as the tunnel bushing?

[darcher]

Original. You think that's it and not in the transmission?

[timmy2]

Some play in the bushings may be stopping full engagement allowing it to slide out some. Definitely worth a try as it's a Cheaper fix than a worn syncro on 3rd...

[Jdub]

Replace those bushings (cup under shifter; rod in tunnel; coupler) and experience a world of difference. Leave the coupler cover off so you can continue to adjust the coupler to the shifter over time. Adjustment = perfection!

[Bob Kontak]

Originally Posted by timmy2

How old are your shift coupler bushings? Also the shifter ball and cup as well as the tunnel bushing?

+1 There are several "slop" points in the mechanism that you can tighten up inexpensively.

Also the seine shifter site has a page for blueprinting the factory shifter. I performed procedure "D" and it quieted my acceleration rattle.

Seine Systems > Blue Printing the 915 Shift Housing