TR6 Transmission Number Meaning

[CaptBob]

Could I please ask if someone can interpret these identification numbers on my "new to me" 1971 TR6 transmission housing? My hope is that the OD means it's an overdrive transmission, but there is no control mounted on the steering column.

Thanks for any help/advice.

Capt Bob

 

[CJD]

The casting date looks like 12/1/1970. I don't know what the stamped number is...either VIN or tranny sequential number would be my guess.

 

[charleyf]

The bestway to tell if it is an overdrive tranny is to just look at it. If it is a non overdrive the rear 40% of the tranny is tapered to the output shaft.
If it is a overdrive tranny the rear portion has a rounded almost ball shape directly behind front half. It also weighs a bunch more.
Charley

 

[titanic]

My guess is that what you are interpreting as OD is actually CD, which is the correct prefix for a trans. from 1971 vintage. My 1971 TR6 trans. is CD 37315. I don't know is OD was ever denoted on the trans. as the OD would have been added after the manufacture of the trans. As Charlie mentioned, just check the pics of a OD vs non OD trans.
Berry

 

[mctriumph]

Historical factoid, the OD was a dealer installed option also. In 1957 it was 175 $ to have it after the sale.!!
Of course that would be in excess of 2000 $ today. "Your cash aint nuthin but trash"
Mad dog

 

[RGK]

The first character is a C. Zoomed in on the picture.