* Allison 1000: This is the more common transmission for heavy-duty applications in that year and engine combination. It's an automatic.
* 4L80-E: While less common with the 6.0L in a one-ton, it's possible, particularly if it's a lower-spec model or a special order. This is also an automatic.
To know for sure, you'd need to check the vehicle's identification number (VIN) or look at the transmission itself for a casting number. The VIN can be decoded to identify the original transmission installed.
