1991 560SEL transmission
 

when traveling about 40 MPH, slowing (but not too slow) to turn hard right onto side street. speed after turn approx 10 - 15 MPH, hit the gas lightly, transmission speeds up for a split second then shifts kinda hard. otherwise, transmission shifts perfect at all times. I am thinking either engine vaccuum or torque converter.....any ideas?

You are low on fluid, when you turned, the pickup started sucking air.

Jim

actually, the fluid is about a half quart too full (approx 1" over top mark on dip stick) when checked idling hot on level ground. i'm starting to think this is just the way a benz transmission shifts.....

No, it's not the way it should shift.

If it's only doing it on a turn, I'm still suspicious of the level.

Maybe the dipstick is the wrong one?
Maybe the filter is plugging?

Your symptoms are still the classic indications of low fluid level.

Jim