915 gearbox question

[Sgrun]

I have a 72 911 vintage racer. Being a 72, that means that I am stuck with one of Porsche's biggest mistakes, the dreaded input shaft seal installed from the differential side.

After a couple of on track seal failures, I have had enough and am going to rebuild it in a newer case. All of my internals are in very good shape and can be transferred to a newer case.

One question I have is whether or not the input shaft sealing surface was changed at all when the seal was installed from the clutch side of the gearbox (properly).

Will my internals work with a newer case without further modifications? What years, or will it be all ? Any other pitfalls with my plan?

Thanks,
Steve

[Grady Clay]

Yes, the input shaft ground seal surface did not change. You can use your input shaft in a later case.

Search Pelican on ‘dam seal’. This is useful for any seal configuration, even 356 to 997.

If you change to an aluminum casting, be sure and measure the bores of the pinion & input shaft bearings. Out-of-round is all too common. You might consider a WEVO case for durability.

Do you have an electric oil pump, filter, magnets and cooler? The life you save will be your 915.

Best,
Grady

[RWebb]

Wevo has some sort of fix that may help you.

some reading:

http://forums.pelicanparts.com/porsche-911-technical-forum/332597-best-year-915-transmission-post4242866.html#post4242866

[Steve@Rennsport]

I would use a late ('77) mag case for your application. In some respects, its better than the later aluminum ones unless all the modifications (Wevo) are made.

Naturally, you should replace the differential carrier bearings and 4-point bearing when you do this. You will need to measure and adjust pinion depth and ring gear backlash.

[Sgrun]

Hi Guys,

Thanks for all the great info. - Steve is there something special about the 77 case, or do you mean 77 & later?

Any idea what type they would be? 915/??

Thanks,
Steve