Is there a way to tell when the tranny was built?
Original TH400

There should be a julian date on the identification tag on the side of the tranny. The tag should have two big letters on it like C Y or similar. Get the numbers from this tag, if still existant and tell us more.

Dave

Is it supposed to be like rivited to the passengers side of the tranny?
The numbers on the pad on the drivers side is 10L150875

I think it is on that side, I don't recall which side for sure. It is a tag about 1 inch by 2 inches, and should have the letters CW or CX IIRC, and it is riveted to the trans.

There is a small alluminum tag that is rivited onto the center area on the pass side of the trans. There should be a 3 digit number stamped in the center area of the tag near where the rivit is. That is the Julian date code. Hope this helps. I have two TH400 Chevy trannys sitting in my garage. I was able to decode them using info from this site. One is a 1970 that came out of a Chevelle 454 and the other is from a 72 396.

The number you posted is the partial vin of the car it was installed in
1=Chevrolet Div
0=1970 model year
L-LosAngeles assembly plant
150875= car sequence number

Rene
66_Malibu