I just purchased a 1981 SD. I was going to verify which transmission it has and found the numbers that should have been on pad above pan on right side were milled off. There is a tag riveted on left side above pan that indicates it is a MB reman (exchange) unit. The numbers on tag are TEIL NR. 123 270 5901 and AGGREGAT NR. 164187 . Using this info, how do I tell which trans I actually have? On the right side of the case, it has numbers cast into it which are 33.4920.00 with 126 271 1501 below it-not sure if these numbers will help. As a side note, i need to buy a filter along with a B2 piston for this trans which is why i need to know.

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1982 240d 4-speed-sold
1981SD-also sold

If it’s a reman i am surprised MB would erase the 722 numbers and serial number. Why do need a B2. Mercedes
Reman transmissions have the B2 bore, milled to a bigger diameter, the “T” used in these units are bigger.

The replacement B2 piston is the SAME part number for ANY 722.3! On some transmission additional parts are required to install the new piston.

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ok-thanks mb doc! Right now, the transmission has good reverse but no drive unless you rev motor. So after researching threads it seems that B2 valve is the reason why. I just wanted to get all my info before ordering parts. The pan is a 6 bolt. The numbers are milled off with an end-mill. It has some red rtv on the back of it-maybe it's a rebuild of a MB re-man/exchange trans?

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1982 240d 4-speed-sold
1981SD-also sold