I have a 1990 300D 2.5 Turbo with a problem.

I was having a power problem with my 300D, and discovered a torn vacuum
line on the turbo actuator!  Fixed it and the power seems to be good.
However, I'm noticing the trans is shifting through the gears to 4th
before I hit 20 miles an hour, and even the firmest foot to the floor
will not initiate a down shift.

I can do it manually from the console, but curious if anyone can point
me to the likely component, or adjustment.  Could it be yet another
vacuum line.  I've looked but have not found one amiss.

The machine has 160K miles on it, and is running great, save this
little quirk.

Tim

P.S.  I won't go into detail, but my confidence in Mercedes dealer
mechanics is at an all time low.  A lot of Bozo working those things in
my experience.