CEL comes on and tranny throws P0717 code

21silverado2.7 · October 17

My truck is a 2021 Silverado Custom Crew Cab with a 2.7L and an 8 speed trans. I bought it wrecked ( i work at a salvage yard). It was hit in the LH rear and had driven the rear end back. I replaced the axle shaft and bearing. Housing is straight. I went through a spell where the transmission would shift hard , the CEL would come on and i would be stuck in what felt like 2nd gear and a code of P0717(input turbine speed sensor issue) would come up. We noticed that the rear end appeared to be back on one side. Apparently the guide pin on the leaf pack had broken and allowed the rear axle to slide back. After putting a new spring pack on, all of the wonky issues resolved immediately. That was 6 weeks ago. Tonight, out of nowhere, the CEL came back and I'm stuck in 2nd again. Usually if i let it sit for a bit and start it back up it's fine. Is it actually the turbine sensor or TCM or something else? Also, this seems to accompanied by the radio resetting at random times. Just for like 10 seconds, like it's rebooting. PLEASE HELP!

repairman54 · October 18

Check braided frame ground strap on the pass. side underneath the front door for a poor connection. Especially if your in a salt zone. Common problem that makes the truck do wonky things.

Edited October 18 by repairman54