Transmission number?

Tadpole · 01-20-2010, 04:14 PM

Hello everyone,

The tranny has been changed out by the PO. Can it be figured out from the number that is stamped on the bottom? I can only see a partial number. It is 720075. Is that enough to figure year and ratio? As always thanks for any and all help.

Peter Zimmermann · 05:09 PM

The number you have posted appears to be short one digit. Can you see a "915 xx" stamped next to it?

7 = Trans for 6 cyl engine
2 = 5-speed (possibly 915/43)
0075 = consecutive build number

You're missing the "year" digit... 72 "X" 0075.

Tadpole · 01-20-2010, 05:21 PM

Hi Pete,

I don't see and 915xx number. That side of the rib is a little banged up. It is possible that there is another 7 up front. It's hard to tell. But the number might be 7720075. Is that a real number? Thanks

Tadpole · 01-21-2010, 04:34 PM

This is what I'm looking at.

The PO did work to the engine ( Euro RS spec pistons, solex cams and webers). I'm just wondering if he changed the transmission to get the better gearing to utilize the new configuration.

Peter Zimmermann · 05:05 PM

Mike, can you post a pic of the bell housing?

"7720075" could be a 1972 5-speed, type 915/02, with 7:31 ring & pinion. Does it have a drive for a speedo cable on its nose?

Tadpole · 01-21-2010, 05:07 PM

Hey Pete,
Hope this helps. Thanks for looking.

Tadpole · 01-21-2010, 05:33 PM

A picture of the other end

Peter Zimmermann · 01-22-2010, 07:07 AM

Yep, it's got to be a 915/02. You have the main shaft seal that can be replaced without dis-assembly (good!), and if your car has a cable drive speedo that's good too. Now all you have to do is figure out what's inside! BTW; good pictures!

Tadpole · 01-22-2010, 04:00 PM

Is there any way to tell whats inside without taking it apart? Can I turn the axle shaft and count the number of turns on the splined shaft or vice versa?