Can you identify this part from 915 transaxle
 

I had the 1st gear synchro hub removed from my 1977 915/61 transaxle as part of a rebuild. The serial number on the case is 7176828. I can't figure out which part number to order so that I can replace it. Any ideas? Here is a link to a couple of picture of the removed synchro hub.

http://members.cox.net/chris_thomas/


Thanks,
Chris

unfortunately that part is obsolete, although someone else on the board (jim sims?) apparently found one. the replacement part has angled (assymetrical) teeth, and requires a different brake band and stop dogs, as well as the angled 1st and 2nd shift sleeve. you could make one out of a 2nd gear piece by using a disc cutter to make the extra notch. you can't just use a 2nd gear unit because the 1st gear brake band is designed to allow you to shift easily into 1st at a stop, where if you use the 2nd gear setup, the shift is difficult. update the 2nd gear band and dogs if you update 1st.
part# for new 1st teeth 915 302 241 14
2nd teeth 915 302 242 00

My best guess is that with that many broken teeth on the synchro hub ... you will probably need to replace the operating sleeve (slider) ...so you will have to use the asymmetric later design hub, since no early sliders are still available!

I thought I'd found a symmetrical 1st gear synchro hub. What they had was the 2nd gear synchro hub; the vendor in good faith tried to machine it to the configuration of the obsolete symmetrical 1st gear synchro hub. The machining job was not satisfactory in my opinion (the "clocking" location of the angled slot was off) so I elected not to use it. I sent it back to the vendor and my money was refunded. This machining is not trivial; it requires the tilting of the workpiece or cutter and there is also the concern that the newly cut slot surfaces no longer had the case hardening intact. One can substitute a 2nd gear synchro hub if you also change out the anchor and energizing blocks and add a brake band (option 2 listed in the below link) but I would not recommend this. If I were you I'd just go to the full update (option 4).

http://forums.pelicanparts.com/porsche-911-technical-forum/61521-915-1st-gear-synchro-upgrade-parts-list-long-boring-unless-you-need-info.html?highlight=915

The 1st/2nd operating sleeves (sliding sleeves) are available new or at least they were this past February. When you order parts you may find the number has been superceded to a 930 part number. Jim

My car is going in next week for a trans rebuild - I have a 915/61.

Are these "new" issues, or should the shop already know about them and know the workarounds?

These are old issues; but you should learn if your update will be option 2 or 4. Option 4 is usually considered the best but costs more as more parts are required. This may be moot if the old parts on 2nd gear are worn anyway and warrant replacing. Jim