Worn synchros?

[drsimonwong]

My 915's 2nd gear is behaving erratically. It's in relation to 1st to 2nd upshifts.

In low/mid rpm upshifts from 1st it's really nice. At higher rpm shifts sometimes it's smooth, sometimes there is very stiff resistence. Goes in, but the shift is tight and slow.

At high rpm shifts it's always very tight and slow.

When I double declutch at redline shifts it's as smooth as a hot knife through butter. When I double declutch at low or mid rpms it's sometimes slow and tight.

I corresponded with James as it's more noticable since the Rennshift installment and he thought worn eng/trans mounts and engine torque/twisting of drivetrain but I have new Wevo mounts so that shouldn't be the issue.

Coupler adjustment issue or worn synchros?

Simon

[donstevens]

Synchro - You describe classic worn synchro symptoms and the double de-clutch behavior seals it. If the shifter was out of alignment the double de-clutch would not help.

Don

[drsimonwong]

Thanks for the feedback Don.

Will I do more damage to the drivetrain if I leave things as they are for now (perhaps 6 months or so) and continue to double declutch? Biffed the car into the side of the track railing and all my budget for this year is going into repairs......

Simon

[donstevens]

6 months? No Problem. I drove my 71T with a worn 2nd gear synchro for about 3 years that way. It was worn when I bought it and it was worn when I sold it. As long as your good with the double clutching, and discplined about doing it up shifting and down shifting, you will do no more significant damage to the box. If you do not double clutch you will wear the dog teeth beyond recognition plus all the wear meatal will be floating around in the gear oil.

Don