924Board.org

[palin]

Hi,

This has been an arduous journey. When my crank sensor died, I thought it was the end of world and my imported 932 from South Africa was going to parts heaven. Thanks for all the help here, the car is up and running on 1-2-3 ignition.

However, I have another major issue now and will greatly appreciate any advice. The gearbox is able to go into 1st but always crunches into 2nd regardless of speed and pops out of 5th. My Mechanic suggested to me to just put my hand and hold the gearknob in place whilst cruising in 5th gear (dry sense of humour not appreciated!).

May I know what are my options? Any reputable/specialist shop that can help refurbish this gearbox? Or buy the parts individually and arm-wrestle my Mechanic to repair it? He’s reluctant and was telling me an MG was also going through the process, costing a lot of monies with the owner buying a refurbished box in the end. Thanks for reading.

[Cedric]

In what country do you want it to be located?

I rebuilt my g31 myself(synchros were still good but it leaked oil a bit, but changed 1-2-3rd gear syncs while i was there) , pretty easy gearbox to work with. There's a good online guide if you want to do it locally. The hard part is sourcing the parts, i don't know the current status, maybe Steve (carreraRsR) can supply some more info, he got his box rebuilt recently o think.
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1980 924 Turbo
www.instagram.com/garagecedric/

[Carrera RSR]

It’s not a hard box to rebuild for any good mechanic or Porsche shop to rebuild. All the synchros are available at Porsche using 937, 911 or 928 parts rather than 931 versions which are mostly NLA. The issue will be if you need any dog teeth 1st or 2nd gears. There is a motor sport company in Germany that supplies them for circa €200 each. I can’t find their email right now. But when I had my Gearbox rebuilt they had none in stock. So it never got 100% finished. You cannot swap the synchro without changing a worn out dog, It can potentially lock you out of that gear
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252

[Harm]

[Carrera RSR]

[palin]

Thanks for all the advice. I’m located in Singapore. Is the synchros also known as synchroniser ring under the parts catalogue? The other thing I notice is that the different gear sets always come with a loose gear and a fixed gear (i.e. 2nd gear). Is the fixed gear also known as the dog gear which was mentioned in the thread?

Appreciate the contact for sharks motorsport, will check them out. However, by any chance someone here has used Vertex Auto before? I had been ordering parts through their webpage but not sure whether their skill level or if they can refurbish a G31.01 though they seem to refurb other Porsche boxes.

[kevingross]

Palin, I am rebuilding G31 transmissions, if a US-based option is workable for you.

Yes, each gear is a pair: a fixed and a floating (also called shifting) gear. The dog teeth are pressed onto the floating gear and engage with the shift sleeve to engage the gear. The synchronizer ring is a separate part, and its job is to get the floating gear and the shift sleeve to turn at the same speed so that engagement happens without grinding.
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Kevin
Catellus Engineering, Inc.
http://www.catellusengineering.com/
catelluseng@gmail.com

[palin]

[kevingross]