Swapped in a C6 about a month ago to replace a worn out manual OD trans on my 300 I6 equipped '85 F150. I noticed I have to really give it throttle to take off from a stop, then it has a harsh 1-2 shift. If I take it easy...I mean really easy, I get a nice smooth shift. When I put it in reverse it seems to engage pretty hard.
I can back out the screw on the modulator but that softens things up too much.
My thought process is that since I'm having to use a lot of throttle to get going, the trans "sees" low vacuum and wants to hold first gear longer.
Possible wrong torque converter with too high of a stall speed? It's a low mile Jasper reman trans that came with a torque converter. It just seems like the converter feels loose. I can power brake the truck and the engine rpm goes up to 2000-2200 before the engine won't rev any farther.
Its not helping my fuel economy either...lol. I'm thinking it's some generic converter that is set up more for v8 use.