My 84 had a rebuilt tranny put in at about 175,000. I just had to take it apart and replace a defective clutch plate, bad stamping from the factory. My 83 seems to have the original tranny, shifts hard from 1st to second, sometimes jumps over 2nd directly into 3rd, flares from 3rd to 4th, so it is time for that one to done. I know of an 85 300D with around 400K mikes and the original tranny. It also has the original timing chain.

Jerry