81-83 were basically very good transmissions also pretty much just as durable. most issues before the 1985 upgrade had to do with shift quality esp. cold. (shifting aliitle hard ,for a Mercedes owner). In 1985 a high stall torque convertor was also added and allowed the Diesel rear end ratio to gear alittle more towards fuel economy. 85 than began a more complex vacuum system to soften the shift further . This tranny will fit and work very well (with or without the matching high stall convertor) in a 1981-1984 along with some vacuum modulator adjustmenta as mentioned by the doc.