Transmission problem with 2nd/4th gear selection, why does this happen right before a track day!!!! Options

[racerx9146]

Hello, I could use a little input on this one.

So less than 11 days to a non-refundable track day at Thunderhill and my tranny won't go into 2nd or 4th. I have disconnected the linkage and cannot engage 2nd or 4th manually. 1st, reverse, 3rd and 5th are fine. It's like there is not enough throw at the side shifter input dongle. It also seems to require a lot of throw to get 3rd/5th engaged to the point that the ball is starting to pull the bushing out of the socket.

Its a 914-6 transmission rebuilt and converted to side shifter by a local Porsche "specialist". About 9 years ago. My tranny has never shifted right since the rebuild and I kept telling myself it was the linkage or something else. Now the problem has presented itself completely! 4th was always "soft" but now its not there at all and 2nd has joined the party. No grinding just no engagement. The car was in project stage for long after the work was done so it tough to try to bring it back to the specialist.

Got any ideas, Is there anything I can adjust with the tranny in the car or should I pull immediately and try to figure it out. I have rebuilt Porsche engines but always stayed out of the transmission world.

thanks Daron

[racerx9146]

Thanks for all the replies and the great picture. Much appreciated. I will pull the comb as soon as I get home from work today and post results. Dr. Evil your theory sounds promising (I hope) but would that not also affect 1st/reverse? Anyway its time to get extra greasy in a hurry.

Daron

[Dr Evil]

Thanks for all the replies and the great picture. Much appreciated. I will pull the comb as soon as I get home from work today and post results. Dr. Evil your theory sounds promising (I hope) but would that not also affect 1st/reverse? Anyway its time to get extra greasy in a hurry.

Daron

My recommendation is purely based on the external cone screws, bushings, adjustments being correct, which you addressed in the first post.

Searching for simple/common failure items is the name of the game. External stuff is first and most common.

Then you get to the selector console which has two roll pins that can fail. Typically they are not spectacular failures, they are insidious like you describe; loss of gears in one direction.

Your question about 1/R is a valid one and when I think about it it does make sense.

1-3-5 are in the same plane and are not impossible to get to.

R-2-4 are in the same plane and 2 & 4 are the ones that are failing. Why not R? Well, R has no synchronization hardware to mess with. It is a straight gear being engaged with a straight gear. No real resistance like 2 and 4. So, it glides right in with little effort. The only resistance you feel is the spring detente.

If it is not the inner roll pin (I will be shocked), you are gonna get into multiple failure points as then you would need two separate bolts to come loose on two different shift rods, and then only shift so that only one way could be selected. Very improbable.