Can't find 5th in 915 transmission.

moneymanager · 12-09-2008, 10:31 AM

Car is a 74 with about 100k miles. I have no reason to believe the transmission has ever been apart. For the two years I have owned the car, getting into first has always been awkward, but otherwise everything worked perfectly.
This weekend at a track event I shifted to 5th as I always do and couldn't find it. I tried again, it went in but didn't feel normal. Did it again, let the clutch out and realized the car was in 3rd! Fortunately I caught this in time. I tried 4/5 times and decided to just stay in 4th.
We looked at the linkage at the track and saw nothing obviously loose or out of adjustment. Driving home, the scenario was repeated. Sitting in the driveway at home I can't find 5th at all.
We'll look again for a linkage issue but this sounds to me like a synchro problem.
I think I remember that you can get to the 5th gear synchros without pulling everything else apart? If that's true, can this be done without dropping the tranny?
Finding 3rd instead of 5th at the 5th position seems very strange. Anyone have any idea how this could happen? Any advice welcome.

PorscheGAL · PorscheGAL's Garage

Try putting the car in neutral and then twist the entire shifter counterclockwise. Someone with more experience will be able to tell you how to make a perm. fix. Good luck

Scooter · 12-09-2008, 11:21 AM

Check your coupler, fist for condition, then for alignment.

Ole Petter · 12-09-2008, 12:01 PM

Check the coupler behind the handbrake. Mine was in small pieces.

A new one made all the difference! Chech that first!

kach22i · kach22i's Garage

Good comments, time to pull that carpet up.

teenerted1 · 12-09-2008, 01:43 PM

yes check the coupler before the rear seats...could be the bushings, could be the set screw.
make sure you mark spine positions before you lossen anything. will make reassemble go much easier

moneymanager · 12-09-2008, 02:10 PM

Coupler is fine. Thanks.

tonythetarga · 12-09-2008, 03:04 PM

looking at your first post and thought on the syncro. As I understand it, if you are sitting in the car, engine off, you should be able to get all gears worn syncro or not. If you can't get it into 5th then, you are probably looking at another issue. If you are certain the coupler and shift bushings are fine and the coupler is properly adjusted, then inside the tranny is next.

moneymanager · 12-09-2008, 04:37 PM

Thanks Tony. The good news is it probably isn't the syncros. The bad news is it's something more expensive!

tonythetarga · 12-09-2008, 05:44 PM

Might not be too bad. I had a student at the track this year that lost 4th and 5th. Turned out to be a loose fastener on the selector shaft. It did require a drop and open heart surgery, but it was not a rebuild. I think he was out the door for $1k, which isn't bad when you open a tranny!

moneymanager · 12-09-2008, 08:14 PM

Well we can hope. Did he see any metal on the drain plug? My next step is to check for big pieces on the magnet!

tonythetarga · 12-10-2008, 04:56 AM

Quote:

Originally Posted by moneymanager

Well we can hope. Did he see any metal on the drain plug? My next step is to check for big pieces on the magnet!

IIRC he said everything was clean. It really was just a matter of tightening up the fastener once the forks were in the correct position.
BTW, you should be able to verify this by removing the side plate on the trans before having to drop it and open it up.

ruf-porsche · ruf-porsche's Garage

Check the plastic cup under the shifter, it is probably worn. When I brought my first Porsche a 1974, it was hard shifting and I thought that I would need to replace either the clutch or tranny, the PO gave me a break and took that into consideration when we were negotiating for the car. Turns out it was the plastic cup under the shifter. A fairly quick and CHEAP fix.

moneymanager · 12-10-2008, 06:12 AM

Many thanks Tony. I'll report back after I get it to the shop. No big hurry, as season pretty much over till March! I'm still puzzling about going into 3rd in the position normally reserved for 5th!

moneymanager · 12-10-2008, 06:21 AM

Rest assured, we will pull cup, coupler etc and check from end to end before dropping tranny. I of course really hope that one of these is the culprit. But as I said at the beginning, unfortunately our quick track-side look at these parts didn't reveal a problem. Thanks.

moneymanager · 01-16-2009, 07:55 AM

A follow up, finally. No chips in the transmission. Another mechanic at same shop, who had had a similar issue with his own 74, readjusted things. Amazingly, so far, we seem to be fixed. I have always had good luck with the simple advice to get the shift stick very vertical, then hold it in position while moving the coupler all the way in whichever direction it goes. He thought it was a bit more subtle than that. But so far so good. Thanks to all who contributed.