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 Express 3500. If your van is stuck in second gear even after installing a rebuilt transmission, it does sound like it may be in limp mode. Limp mode is designed to protect the transmission when the system detects a fault, but if you’re not seeing any codes, that makes things a bit trickier.
Even without a check engine light, there could be transmission-related codes stored in the TCM (Transmission Control Module) that require a more advanced scan tool to read. It’s also possible that the TCM needs to be reprogrammed or flashed to recognize the new transmission properly. Double-check all electrical connectors, grounds, and fuses related to the transmission—sometimes a simple connection issue can cause strange behaviors.
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!
