915 Refresh

[Daviboy]

Hi guys my 915 gearbox now has +152,000 miles on it and I think it is time to think about replacing the 1st and 2nd gears and synchros for the following reason.
History of the gearbox is unknown I bought the car with no history at 140,xxx miles in 2008 and since then have completely rebuilt the motor but never touched the gearbox.
Always had a slight issue with 1st and 2nd, atypically like most 915’s I have read about she is balky going into 1st especially when cold, also balky 1st to 2nd although with a gentle change or double declutching is fine however this can get onerous. When shifting down to 1st the timing has to be very careful i.e. when rolling to a stop depress clutch and let her slide in.
3rd, 4th and 5th are smooth no issues.
Now I know that none of the above scenarios mean very much but I just feel now that I have a great running motor I would like to refresh 1st and 2nd.
I know this is achievable for me having done the motor I am just unsure of exactly what parts are required and what the correct procedures are to do this.
I have read Pete Zimmermans Porsche 915 Transmission Repair Tutorial but it is more specifically aimed at a complete rebuild.
Can one of you kind fellows point me in the right direction as I don’t want to spend $$$ on something I don’t need.
I have searched but as is often the case the results don’t always address the search criteria and right now I don’t have the time to sit and trawl through 10s of posts no matter how interesting to find the definitive answers

[Nick Triesch]

Wow! That sounds just like my tranny! Are you sure you don't have my car? I was told by a pro that when the time comes it is best just to do the entire gear box. I mean if you are going to take it all apart anyway. Most shops will not even do a partial rebuild. Must be a reason. I think they don't want to see it again. Nick

[yelcab1]

dog teeth 1/2
slider 1/2
synchro band 1/2
oil
gasket kit
special tools
inspect to see what else you need. Most likely the case has to be repairt for spun bearing

about $1500 worth

[Peter Zimmermann]

Davy, "yelcab1" said it. The problem that I see in these gearboxes is that the rear pinion bearing outer race gets loose in the diff housing. This repair requires dis-assembly. You're between a rock and a hard place regarding mileage because the bearings, especially the four that are clustered together on the P/S & M/S, should go another 75K miles, but maybe they won't. Tough call, but I think that it's got too many miles to not do a complete dis-assembly and diff carrier bearings.

[Daviboy]

Hmm I was afraid you were going to say something along those lines Mr Zimmerman. My dilemma is that I live in Cape Town South Africa and apart from the local dealer who has an outstanding 'older 911 mechanic' who works at preferential rates there is no one else I would trust to perform the rebuild. Could be very very costly considering I want to get the car repainted and have the interior brought back to original specification.....

[Joe Bob]

I delivered my case to Dennis Aase. He pressed in a sleeve for the bearing and I installed a WEVO plate to tie in the two shafts.

Shipping a bare case shouldn't be too expensive and Wayne's book does a good job explaining the rebuild process. I robbed a 915 for parts and used it to rebuild what was broken. There are a few tools needed but they can be fabbed with a welder and old clutch pieces.

Contact Ingo at 3.6@cox.net he can also give you helpful hints.

[revmax]

Follow Zimmermann's lead and use his 915 rebuild tutorial as the guide. He's the master... Good luck