Trans

[Wilbe29]

How to tell what year four speed I have I was told it was 57 but I'm not sure how to tell

[RUBONE]

On the bottom there is an oval shaped raised place with numbers and or numbers and letters in it. That is the date code.
Do a search on here for tranny date codes, there is a ton of information courtesy of our member Speeding Big Twin, from Oz.
Use the Knowledge base, it is your friend...

[Speeding Big Twin]

Did you find a date code? If it’s really a trans case from a 57 model then the code may be 3 3 because that code has been found on trans cases of bikes as late as 1956–57 models that are unaltered from original. At first that code may have indicated casting in March 1953 but 3 3 then remained in use for some time for reasons unknown. After 3 3 the next code I know of is 1 58 for Jan 1958 casting.

Below is a link to some info I posted recently and it contains a list of some date codes along with some other ID particulars. If your code isn’t listed could you let me know so I can add it to my collection. Thanks.
Eric

Date codes and other info for some, not all, BT trans cases