Hi, my name is Devin. I am an auto repair expert with the Car Genius team here at RepairPal. I'm sorry to hear you're having trouble with your Silverado 2500 HD.
The "Service 4x4" message after installing the transfer case control module (TCCM) could indicate the module isn't communicating correctly with the vehicle's CAN (Controller Area Network) system. Modules often need to be programmed to work with your specific truck. The replacement won't function as intended if it hasn't been programmed.
To resolve this, you may need to have the TCCM programmed with GM-compatible software, which can be done at many shops or with a J2534 programmer if you have access. If reprogramming doesn't work, exploring reconditioned OEM TCCMs from trusted sources like salvage yards or online sellers may be a good option.
Another route is contacting companies specializing in remanufactured or custom modules tailored to your vehicle, as they may provide a solution that works with your truck's system.
If you need more advice, have any other questions about your vehicle, or would like to get connected to a RepairPal Certified shop near you, we have you covered. Give us a call at 877-913-1554, and we will happily help you out!
