Early 70s mag case 5-speed

[Wolvega]

Hello all, looking for an expert eye. This came out of my '78 SC. At PS-Rispens in the Province of Drenthe this morning, the mechanic said that it might have come from a '72 or '73. Can anyone tell me anything more about it?

[nickelplated5s]

ID # and or pics.

[Wolvega]

Slow on the uptake...

[nickelplated5s]

Pics didn't load.

[Matt Monson]

Has electronic speedo and appears to be aluminum. Going to be something like a 915/61 or 915/63. Type number is on the rib on the bottom. Sc or later.

[Jack Olsen]

Are you sure it's magnesium? I thought 1977 was the last year for that.

[E Sully]

[gled49]

Looks early, 73-74, based on the detent plugs. Electric speedo wire but nowhere to put the sensor. Something weird at mechanical speedo end. Need front bellhousing pix to observe input shaft/guide tube. It has late drive flanges but that’s easy. It’s also not a Chromadora case.

[Wolvega]

No question but that it is magnesium. Its after 23:00 here, front bellhousing photo will follow tomorrow morning... Thank you all to this point(!).

[Tonger]

CMS - California Motorsports has a great page on Porsche 915 specs. Once you find the id on the bottom of the case 915/xx, this will tell you the rest.

https://californiamotorsports.net/pages/porsche-915-transmission-specification

[Wolvega]

No ID number on the very bottom of the case. Doesn't actually seem to have been one. The cable worked/works fine.

[Matt Monson]

Clearly an early one, based on the guide tube.

That tailcone is something weird. It's got electronics where the mechanical speedo drive normally resides.

[Wolvega]

Actually, the cable is just loose, not plugged in hanging over the tranny. Looked at the bottom closely today, no 915/xx number; a small type set part number on a small plate in that area though.

[Matt Monson]

That’s the serial number. It will start with 7. Second number is the spec. 3rd is the year and the balance is sequential.for however many they made that year.

[Wolvega]

This is all that's down there...

[Matt Monson]

Oh, sorry. That’s just the cover plate casting number.

[E Sully]

The number is on the bottom ridge, but is commonly worn down.

[Wolvega]

Yep, that's gone.

[E Sully]

I am far from expert on transmissions, but from what I have read it seems to be a late '73 to early '75. It closely resembles my late '73.5 915/02 transmission, except for what is connected to the speedometer drive.
This picture supposedly show the '72- early '73 guide tube that needs to be taken apart for seal change.



Later ones had this tube which could be removed and replaced without taking it apart.



This is my '73.5 transmission which seems to be similar to yours.




Early Seal: 999 113 182 00 Type G 733 7374 and earlier
Late Seal: 915 302 381 00 starting with Type G 733 7375
1976 went to removable guide tube and electronic speedometer.

[Wolvega]

Thank you very much E Sully. Not an expert? Horseshoes, hand grenades and early 70s 911 transmissions.