[chevy561]

Hey guys,
I have a '56 Chevy that has a bad 3rd member and have purchased a used replacement from a friend. He told me he thought it came out of a 1964 Chevy, but don't let this influence your thinking. It seems to be in real good condition but my questions are:
1. The casting number is 3725889 do any of you know the year this was used?
2. The stamped ratio code is BA 805 and I know the BA stands for a 3.55 made in Buffalo but what is the 805 numbers? Also just above the stamped numbers is a stamped letter "H" (without the quotes), any idea on this?
Thanks a bunch.

Adrian

 

[TOMMY454]

The casting number 3725889 I found it's either a '55 with 3.55s or a '57 with 3.36s

 

[Rick_L]

Or any ratio from those years.

 

[chevy561]

Since my friend that I bought it from thinks it was from a '64 Chevy do you reckon GM used the same casting from 1955 up thru 1964?

 

[Rick_L]

Not sure, but I think maybe all non-posi cases from 55-64 were the same casting # (899).

There is a code stamped into the housing on the passenger side mid way up. It's a combination of letters and numbers and will tell you where the pig was built, what the gear ratio it was originally built with, and a date code. Likewise there should be a date code near the casting number on the driver side.

 

[tony7538]

I just took apart my 57 , and the casting # was the same with a 336 ratio

 

[chevy561]

Thanks for answering guys,

Based on your answers it sounds like they used the case for all 55-64 years and all possible ratios that were not Posi-Trac. Also, since you mentioned the date code was next to the casting number I'm guessing that the "805" that mine has would mean the original build was 8th year (1958) and the 5th month of that year. If my thinking is wrong let me know. Thanks again for taking the time to answer my questions.

Adrian