The transmission computer decides when and how your gearbox shifts. Manufacturers call it a TCM (transmission control module), a TCU (transmission control unit), or a transmission control computer. On many vehicles the transmission logic lives inside the PCM instead, which is why matching your original part number matters so much.
Symptoms of a failing TCM or TCU
- Harsh, delayed or erratic shifting, or the transmission stuck in one gear (limp mode)
- Transmission-related trouble codes that return after mechanical repairs
- No reverse, or the vehicle will not shift out of park
Before you order
Confirm the part number on your original module, your engine size, and whether your vehicle is 2WD or 4WD. Transfer case control modules are listed here as well. If you are unsure, send us your VIN and we will verify it for you.
