Difference between 915’s

[911+1]

Had some major work done on my’74 911 and was surprised when
the shop informed me that the transmission was from a ‘72.
Are there any differences between the two years?
Thanks,

[Jon B]

Are there any differences between the two years?

Tony, in most respects they were the same.
The gear ratios were different, and the 72 input shaft oil seal could only be replaced from the inside.

Jon B.
Vista, CA

[911+1]

Thank you Jon. The input shaft oil seal is what tipped the shop off to the year. Guess it’s a one year thing.
Tony

[Jon B]

Thank you Jon. The input shaft oil seal is what tipped the shop off to the year. Guess it’s a one year thing.

Tony, from mid-73 through 75 the oil seals could be replaced from the outside with special tools.
From 76-on the guide tubes containing the oil seals were removable.
Many times the 73.5-74-75 transmissions are mistakenly identified as having oil seals that cannot be replaced from the outside, due to their non-removable tubes.

Jon B.
Vista, CA

[911+1]

I’d imagine the serial number would help?

[Jon B]

I’d imagine the serial number would help?

Yes, or the transmission type, if they're still visible and not heavily scraped. A photo would be good, if you cannot read them clearly.
The numbers were stamped into the lowest point of the transmission, just to the rear of the drain plug.

Jon B.
Vista, CA

[Arne]

The numbers were stamped into the lowest point of the transmission, just to the rear of the drain plug.

Typically scraped or ground down to oblivion, by now. Great thinking to stamp those numbers in the very lowest clearance part of the car. Mine is totally destroyed, as were the numbers on my friend's '73.5.

[911+1]

got the car in the air and it is a '74 according to the serial numbers. 7340982
thanks for the assist.
tony

[Jon B]

...the shop informed me that the transmission was from a '72.

The input shaft oil seal is what tipped the shop off to the year.

Many times the 73.5-74-75 transmissions are mistakenly identified as having oil seals that cannot be replaced from the outside, due to their non-removable tubes.

got the car in the air and it is a '74 according to the serial numbers. 7340982...

Yes, I thought they might be wrong.

The shop saw the non-removable guide tube and mistakenly assumed it was a 72 transmission.
The guide tubes were only removable from 76-on.

The seal in your 74 transmission can be replaced from the outside, using special tools.



Jon B.
Vista, CA