I'm currently dealing with a transmission issue on a 2011 Silverado. Here's the problem: the truck refuses to shift to 2nd gear when in Drive mode (Auto). However, when I switch to manual mode and drive for a bit, then switch back to Drive mode, the transmission operates normally. Here are the details:- Transmission fluid level is optimal and the filter is in good condition.- There are no ECM or TCM trouble codes indicating transmission issues.- However, I am receiving TCCM codes C0306, C0392, C0321, and C0396.This only affects 4WD operation isnt it? I've already checked the basics like fluid levels and filters, and everything seems fine in that regard. Has anyone experienced a similar issue or have any suggestions on how to further diagnose and fix this problem? Thanks in advance.

 

I would check all the wiring harnesses and grounding points underneath. whatever is affecting the TC may affecting the trans.

 

I removed the valve body from the transmission and took a photo of the clutch gaps underneath. I noticed there's enough space to fit a 3mm diameter screwdriver inside. Is this amount of gap normal for the clutch assembly?