Can extra trans cooler affect shift quality?

[davepl]

I was wondering - if, like me, you plumbed your automatic trans through the factory radiator cooler and an auxiliary cooler, I've heard that doing so can increase the pressures in the transmission.

Does anyone know (a) if that's true, and (b) whether it can change shift feel as a result?

I have a 4L80E in my truck plumbed that way and wonder, as it's supposed to be a completely stock rebuild but it shifts 1->2 very crisp if you have any RPM going at all.