I could use some advice from the automatic transmission experts out there.

I have an 80 300TD with an OM617 NA and automatic transmission. The car has been sitting for about a decade so it only has 265k. However it will need some major maintenance and brake work before being put in service. So far I have only yard driven it and the other day I noticed a slight shudder when going into reverse.

I have no direct experience with Mercedes automatics outside of a few short drives. I much prefer a manual transmission and I have all the parts to convert this car but my daughter will need to drive it and hopefully my son will learn on it.

My questions are what can I expect from this transmission generally? Is 265k near the end? Outside of a filter and fluid change what maintenance items and adjustments are critical to longevity? For instance, should the B2 piston be replaced preemptively? I'd like to freshen the transmission and squeeze another 25k out of it if possible. Am I nuts? Wait I can answer that last one!

Any help is appreciated.

__________________
1969 220D 5 Speed (OM616)
1983 240D 4 Speed
1985 300D Auto 376K
1985 300D Auto 275K