trans temp sender location

[ss3011]

Typically the converter charge pressure is regulated, this is what goes into the converter. The outlet of the converter goes first through the cooler, then all of that is plumbed through the lube system (gears, and clutch plates). If changing the case and pump affected the restriction in the cooler loop, it could change the converter charge pressure which could change the efficiency , that might get you the 400 rpm. The problem is you are getting less lube to the gears and clutches, which means more transmission maintenance, might be a good trade off if the on track performance is improved.