915 gear and brake band diagnostic...

[len911]

I'm helping a friend by rebuilding his 915. I recently did mine and came out quite well... When I opened his 1st gear synchro assembly, I noticed that the stop block was at he 8:00 position instead of the 4:00 position. I have followed various 915 rebuild threads and the stop block always points to 4:00. Was this assembled incorrectly by the previous re-builder? Does orientation matter?



Also, I noticed that his fixed 2nd gear has some scoring on a few teeth. He had been complaining of noise. Any ideas what might have caused the gear to get trashed?



Thanks!! Lou

[john walker's workshop]

yes, the band is backward. scoring? that's scoring if i ever saw it. lack of lube is the usual culprit. both gears need to be replaced of course. are the other gear sets ok? hard to believe only 2nd suffered.

[dentist90]

This is the orientation of my 1st gear when I disassembled it. Hmmmm... I thought something looked fishy.
I wonder if this helped contribute to the band's premature wear (less than 40,000 km since last replaced)?


On a related topic, my anchor block has a bit of a bevel to one side of it. Is this normal, and if so is there a correct orientation to it?

[len911]

Funny you mentioned the band wear... On 1st gear, I can actually move the brake band inside the dog teeth very easily. The trans was rebuilt 2 or 3 years ago... Car is barely driven on the street but sees track duty. I'm just wondering if the dog teeth were ever replaced in the rebuild or the wear is from the incorrect assembly... Also, there does not seem to be any wear on the other gears. Trans always had Swepco. From what John says, looks like a lubrication failure...

Dentist, I would replace that blocking unit. They are cheap. I think you want full straight engagement and not cocking the brake band... Lou