How long can I expect the auto? trans to go on my 1996 E300D
 

I have 114k miles. What am I to expect for the life? What will it cost me to overhaul? Can your regular auto trans shop be trusted to do these tras overhauls?

It's impossible to answer this. It depends...depends on how the transmission's been maintained (regular fluid/filter changes) and how it's been driven (more highway than city). My guess would be that if properly maintained and driven with a normal mix you'd easily see 200K miles out of it, and probably closer to 300.

A rebuilt unit costs a couple thousand bucks. I would not have a shop rebuld it, I'd just have it replaced with a rebuilt one from a reputable source that came with a good warranty.