993 G50/21 unusual syncro wear

[Raceboy]

Had the gearbox rebuilt with new syncros (3rd and 4th were grinding before) and all the clearances checked by Porsche factory manual. Everything was perfect but just after few hundred km's 4th gear was sifficult to engage. It did not grind, it just did not want to go in. Downshifting was working perfectly, but upshifting was very bad.
Clutch does not drag, clearances were checked, bled perfectly, starts to engage at ~1/3 distance from the bottom when engaging.

Any experience with that kind of abnormality?

[Matt Monson]

What was the measured gap when installed new? What brand are the synchros?

[Raceboy]

I have to ask the measured gap but iirc it was ~0.95mm or so. Syncros were original Porsche, purchased from the dealer.

[Matt Monson]

Then most likely culprit is the cone on the dog teeth is worn out. You need new dog teeth.

[Raceboy]

Thanks for the hint Matt, will check it soon.

[Matt Monson]

See how your synchro only shows wear right at the bottom? It's not making enough contact with the cone until it's under full pressure from the slider.