Throttle

Can you post a link, it’s hard to navigate this website

Hey guys, recently bought an 01 Silverado from a guy that said he swapped the transmission out with an 03 sienna. I believe both to be 1500K. The truck doesn’t want to shift out of 2nd-3rd. Guy told me he thinks it’s in limp mode. He had a guy run diagnostic computer but wouldn’t read a trans. So my thought is, is the wiring harness different? And if so, I’m having trouble finding pin diagram that shows the difference. I have found the 4l60e Harness diagram, but are they different in Chevy to gmc?