2008 Silverado 1500 P0741 Fault Code: Diagnosis and Solutions for 5.3L Flex-Fuel 4x4 with 33" Tires

Hello, I'm seeking expert advice on a persistent P0741 diagnostic trouble code (DTC) on my 2008 Chevrolet Silverado 1500 5.3L flex-fuel, 4x4 model equipped with 33" all-terrain tires. The truck has been lifted and fitted with larger wheels, which may affect speedometer calibration. I understand that P0741 indicates a pressure regulation issue in the transmission's 2nd gear solenoid circuit. Despite extensive troubleshooting over more than a year, the code continues to appear intermittently. Here’s what I’ve already done: - Replaced the transmission wiring harness (purchased from dealer) - Replaced all transmission solenoids in the transmission case (mechanic service) - Replaced the Transmission Control Module (TCM) and performed a software flash - Replaced the torque converter (mechanic installation) - Conducted a full transmission fluid flush with system cleaning The truck performs normally under daily driving conditions. There are no noticeable shifts, clunks, or performance issues. The transmission temperature remains stable around 212°F, slightly rising on long-haul highway drives (e.g., AZ to CA). The only symptom is the MIL light activating intermittently. My observations: - When I drive aggressively—such as accelerating hard past 45 mph or maintaining speeds over 80 mph—the P0741 code tends to reappear. - If I 'baby' the truck (drive gently, maintain steady speeds around 65–75 mph), the light often stays off for several days. - When driving with my brother-in-law, who has a more aggressive style, the MIL light activates and remains on—suggesting driver behavior may influence code activation. My mechanic is experienced but equally frustrated. His next recommendation was to replace the entire transmission—a significant expense given that the truck otherwise operates perfectly. Given all this, what other diagnostic steps should I consider? Thank you in advance for any insights or suggestions! Additional details: The truck has 174,000 miles on it.