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CMXXXI · Joined: 05 Nov 2002 Posts: 1939 Location: Vicksburg, MS

As some of you may remember, I have been getting my car repaired and refurbished after it sat unused for about 13 years. One of the problems was that the transmission gears ground when I tried shifting into reverse, first and second gears. The car did this from the day I bought it in Germany back in 1984. I suspected that the synchronizers needed replacement from the start. I finally got the repairs done and want to post what I did and how, so that any others out there who need to perform this work will have the advantage of a first hand account.

I’m going to split the posts up into three sections:
1.) Transmission removal
2.) Disassembly & reassembly
3.) Reinstallation (not completed yet)

First, this is the first time I’ve done this work on my Porsche. Some may criticize me for attempting the repair, or my methods. But, it needed to be done, and I felt confident and competent enough to perform the work. Besides, I can ill-afford the dealership shop rates. My car is a 1979 European edition 931 with a G31.01 5-speed “snail shell” gearbox. I understand that the non-turbo 016/Y and 016/Z gearboxes are very similar in design (but not identical) so these comments and instructions will probably be helpful.

Here’s a link to the first two parts.
http://www.924board.org/viewtopic.php?p=59009#59009
http://www.924board.org/viewtopic.php?p=59011#59011

There is a link to a “photo essay” in the second part.
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'79 Eurospec 931

shenry1307 · Joined: 11 Jun 2003 Posts: 43 Location: Chester County, PA

Did you file down the sharp edges at the ring openings? ... Doing so makes shifting much easier and reduces overall wear on the rings.

Also, I assume your shift configuration is "Z" vs. "H", yes?
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'79 EUR 931 (Modified)
"Excuse me, but have you seen my mind?"

CMXXXI · Joined: 05 Nov 2002 Posts: 1939 Location: Vicksburg, MS

Nope, I installed the synchros just like they came. I hadn't heard that filing the edges would help. By looking at how the things work, it doesn't look as if it's going to harm anything as long as there aren't any burrs on the edges.

Wish I'd have known, I'd have sure done it. But, I'm not going to pull that puppy and break it down again just for that.

Maybe at a future date, like if it sounds as if the bearings are going I'll "retrofit", but for the time being I'll just have to keep what I've got.

Shift pattern is: Reverse - left and forward, 1st below that. 2nd and 4th are forward "center" and "right", with 3rd and 5th below them.
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'79 Eurospec 931