How do the factory vans run the 4l85E? I have finally found a engine and trans for my c10 swap, but it doesn't have the ECU's or body harness. How different is the van harness from the truck harness? I have a truck harness and that I was planning on making a standalone, but I am not sure I want to do a manual valvebody or a separate standalone trans controller. I have a ls 4L80E wiring I could use, but I don't what GM used for a TCM in the Vans.