A 1985 300d t is a one year transmission if you want to swap it you will not be able to use a 300sd transmission. You can use an older 300d transmission but you will have to change the transmission lines to older ones and you will have to change the natural safety switch. I will be attempting this swap on my 1985 300d the end of next month. The only used 1985 transmission I could find and I tried at least 30 major wreckers was for $900 with a 30 day warranty if you search my name you will find several post about finding grey market import transmission for an 85 well it’s the same transmission in the CA 300d Turbo and that’s the only year they used that transmission. What a pain in the bottom.
Dave S San Jose CA