NHTSA Complaint #11427253 — 2015 GMC ACADIA

I have taken the vehicle to be repaired 5 times already and GM still refuses to acknowledge the full extent of the issue. My transmission was repaired under 100k miles while under warranty coverage for a slipping 3rd gear, excessive shudder, and hesitation. After a 3 attempts for repair, the 4th involved keeping the vehicle for a number of weeks and replacing internal transmission parts. Within 2 months, the symptoms returned but was out of warranty. The service center refused to diagnose it further without a $1,500 "diagnostics fee". I have brought the vehicle multiple times to the dealership, and have contacted GM seeking assistance on the matter. While the dealership service centers continue to focus on other parts and/or smaller sub-components of the transmission, my vehicle remains UNSAFE to drive outside of my immediate locality. I suffer from stalling, failure to maintain speeds, I cannot pass vehicles, I cannot maintain or obtain highway speeds to keep up with traffic. I have taken it yet again for repair, where the service center refuses to acknowledge the problem. They blamed it on a sensor and sent me on my way, but not only 30 minutes later did the symptoms return full-force. The Check Engine Light has reappeared. Prior to the visit earlier today, it was recently tripped at P0796, Pressure Control Solenoid C stuck or closed. I was on the highway today with avg traffic going 75 MPH. I was unable to merge into traffic and almost got pushed off of the road as a result. The truck also slipped when travelling inclined over the walt whitman bridge in to Philadelphia. It resulted in a bridge closure for 45 minutes while I could get towed off of the bridge. Once i got to the service center, as always, but will not drive over 45 MPH unless its up to 4600 RPM, steadily. This has got to end. Please Help.