i have just done a frame swap where i left all the running gear and engine loom on the frame while i lifted up the body and did the swap---i had driven the donor unit for quite sometime and all was well---after the swap i noticed when OD was applied i would get a fluttering feel like fuel was lacking----did the diagnostic--showed low voltage and purge valve not grounded----swapped in the purge valve----diagnostic is clean---same effect---swapped the vehicle computers (both 2000 auto 2wd) same fluttering--diagnostic still clean------color me baffled....bob

Get some Dr. Tranny Instant Shutter Fix. You can get it from a local transmission shop or probably find it on line. It's in a red tube. It's basically like posi-traction additive. Works wonders.

i cant help feeling like i have done something because the donor unit was trouble free until i sabotaged it with a new and improved body....must look too sleek or something...bob

I know the body controller has the VIN in it , not sure what else it is in and what happens if there is a mismatch somewhere ?

is the rear axle ratio the same between the 2 trucks ?