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