Swapped the transmission VCV and got some interesting results
 

I found a VCV for a 300SD at the junk yard last week and put a mity vac on it this afternoon. It held 15hg, where as my current VCV is holding 12hg. Since I get hard shifts between 1 and 2 when cold, and it slips between 2 and 3 when cold, I thought I would give the newly acquired VCV a shot. The shift between 1 and 2 was seamless and all of the sudden I'm getting really excited. But then, 2 to 3 slipped worse than ever and I even got some slipping between 3 and 4 which has never happened. Even after the tranny warmed up it was slipping all over the place.
Should I leave the "new" VCV on and make adjustments to the modulator, or just live with the lousy shifts for 5 minutes in the morning with the old VCV. The transmission fluid is clean and at the right level.

BTW, Is there a forum member who rebuilds VCV's? I read here that they are no longer manufactured. Thanks

Some of those VCVs are adjustable. You may be able to adjust it and leave the modulator alone.