D Craig,
Great info. Keep it coming. When you rebuild one who's the best source for parts. I have lots of NOS (new old stock) ZF parts from the racing days and my PorschaSports shop owner days. I also use SSF Wholesale and Performance Products for parts. OEM only. No Italian, British, or Brazilian crap. I married into the Behr family and Frau Behr ran Porsche Motorsports Racing for many years so I have some "pull" there if I get in a parts bind. Diter Kirschner worked for ZF until he retired but I can sometimes coax him into hand fabricating parts for me that are no longer available. Diter is older than most rocks now so it's tough even to ask him.
How's Pelican Parts? I have never used Pelican and therefore have no first hand information to offer about them.
What part of the syncros is typically bad and do you replace with stock parts? The synchro ring is replaced while the expanders and anchor block is reused unless damaged. This can be done by hand and requires no tools once the gear is off the shaft. The engagement teeth (sometimes refered to as "dogs"), and the shift fork sliders are replaced if their sharp little points are worn down or worn off. Look carefully at the first picture of a 935 box before rebuild. On the bottom bitter end is the first gear set and the teeth are sharp and good. Next is second gear and the teeth show flatted points. Gotta be replaced. On the upper shaft is third gear with sharp teeth. Fourth gear has no points at all due to a driver jamming into fourth without using the clutch. Pro drivers are an uncaring, brutal lot, eh?
A special is tool used to press the engagement teeth off the gear and the new teeth are heated to 350*F and dropped onto the frozen gear. Tap it quickly into place with a small brass hammer until it seats flat. Seat it quickly or you must start over again.
Are there any parts that should be replace with beefer parts such as the cast steel bearing retainer plate? The steel bearing retainer plate is a non moving part and never wears out . Now and then under high torque and HP conditions, the ring gear cover plate gets pushed out and is replaced by a custom made aluminum billet plate.
