Not knowing much about the computer systems in my truck I'm wondering if the transmission pressures can be changed in a OBDl system with a scan tool? I would like firmer shifts.

Thanks,
Dan

I run a b&m shift plus. Its an electronic module that splices into the pcm harness. It definately firms up the shifts. It has three settings: stock, 1, & 2. Each more agressive than the last. For $40 you can't go wrong. Some will say they like the valve body shift kits better but those don't allow you to switch back to stock shifting and require dropping the pan and the valve body. I have been running this mod for about 5 years now and I have 245k miles on the origional tranny only replacing filters, fluid, and input/output sensors.

you cant change the pressures in a obd 1 sys with a scan tool as lupey6.5 has stated there is other ways to do this though the box that he has basicly puts a resistor in parallel with the force motor in the trans lowering the resistance and allowing more current to flow through the force motor increasing line pressure