1994 E320 Wagon
250,000 miles
original transmission (B3 friction discs replaced about 10K miles ago)
regular ATF fluid/filter changes since new

Over the last 6 months, car has developed slightly harsh upshifts, 3 to 4 shift seeems to be the worst.

I suspect vac mod or vac leak problem. Checked vac system for leaks by visual inspection and with Mighty Vac tool--none found, vac mod circuit will hold 15 inches of vac with no leakdown.

So my question: is it possible/likely that the vac mod is defective even if it holds vacuum?

I did try to reduce pressure slightly be adjusting the vac mod pin--harsh shifts still present. If anything, the adjustment resulted in a very slight flair in the 2-3 shift.

Thanks for reading.

J. M. van Swaay

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1994 E320 Wagon, 230,000 miles
1995 E320 Sedan, 106,000 miles
1994 E500 Sedan, 79,000 miles