Open Road

Sometimes shifts are smooth and firm, sometimes it slams the out of it. Downshifts, 3 to 4, are harsh sometimes too.

No pattern, no consistency.

What I've done:

Replaced the vacuum line that runs from engine to regulator
Checked the vacuum while running, tee'd in a mityvac, normal.
Changed the fluid/filter.
Adjusted the regulator.

Now it's starting to get hesitant on the upshifts.

Low RPM shifts and WOT shifts are fine, normal driving shifts suck.

Check the vacuum regulator itself. You can replace it with a new upgraded MB unit. Roger should have them.

Modulator holds a vacuum well, beyond that I don't know.

I'll look at it. Thanks.

Sometimes the little rubber cap that covers the adjustment mechanism develops cracks.