* Vehicle Identification Number (VIN): This is the most reliable way. Using the VIN, you can look up the original transmission part number through a Ford parts database (like a dealer's system or online parts sites), a vehicle history report, or repair manuals specific to your Explorer's year and model. The VIN will tell you what transmission was *originally* installed; however, if it's been replaced, this won't reflect the current transmission's part number.
* Transmission Case (Difficult and Often Unreliable): Sometimes, a partial or incomplete casting number might be visible on the transmission case itself. This number might be partially obscured by dirt, grime, or the transmission's mounting. Even if found, it won't be the full part number, and cross-referencing it is difficult and prone to error.
* Service Records: If the transmission has been serviced or replaced, the repair shop's records might contain the part number.
* Replacement Parts Receipts: If a replacement transmission was ever installed, the receipt or invoice from the parts supplier will show the part number.
In short, don't expect to find a clearly marked part number on the transmission itself. Using the VIN is the best approach.
