I have an 85 300D...would like to get 500,000 miles out of this...but I have heard that the transmissions generally need work well before then.

I run synthetic trans. fluid, and do filter/fluid changes, including torque converter, every 25,000 mi. (annually) hoping to avert repair work. Fluid is alway pristine when I drain, with no residue in bottom of pan.

Can anyone share your knowledge/thoughts on the general longevity of these transmissions, types of early symptoms of problems, maintenance/adjustments, etc.

This is a great site...thanks to all

Mark