So the new 4r70w is in and it shifts great and runs fine except for one thing, at about 35 miles per hour my speedo says 150+ lol... and i get this "free rev" only from like 1-2 but its doesnt shift hard after the rev.......

car before mine had tune and gears but dustin said that doesnt matter, anyone know if i need a ecu flash and calibration or what? we swapped out my old tranny electrical box thing on the side and that didnt fix it. lemme know what you all think.

this is all witha really bad exhaust leak and one of my o2 sensors insnt plugged in so if that will do something let me know

 

You've probably got the wrong kind of VSS and an unhooked O2 sensor is pretty much junk if you run it like that. You might want to check out Venom's thread on similar issue he had.

 

im gonna plug my 02 in tomorrow and the problem is diff speed sensor