My son was given a 1989 190E. It seems to only have 3 gears. It seems to me it should be a 4 or 5 speed auto trans. Anyone have a clue?

 

So then, this car only has a 4 speed transmission? It seems odd that the car, at 55 mph, runs at 2500 RPM. Any thoughts?

 

the trans is 4 speed. try this: while stopped, shift the trans to the 2 position. accelerate slowly, the trans should start in 1st then upshift to 2nd and stay. bring rpm up to 2500, then shift to 3, the trans should shift up and rpm drop, bring rpm back up to 2500, then shift to "d", the trans should shift up and rpm drop.

my '93 190e 2.3 turns around 3000 @ 70mph.

 

That is it. Operates just like you suggested Thanx.