Dodge trucks manufactured between 1999 and 2003 are especially prone to transmission problems. These trucks used the Dodge 45RFE automatic transmission, which had significant reliability issues.
The Dodge 45RFE transmission was used in Dodge Durango, Ram and Dakota pickup trucks with smaller V8 engines. The transmission's major issues include the transmission randomly jumping into neutral from other gears, problems with shifting to or from certain gears, and overheating. While overheating is often an issue in trucks due to drivers hauling or towing loads over the transmission's safe limits, the shifting problems that affect the 45RFE are caused by mechanical failures.
Dodge trucks with a 45RFE transmission that shifts into neutral unexpectedly often have a cracked flat filter, though this issue can be caused by the filter coming loose as well. This problem allows air to enter the transmission and reduce the transmission's oil pressure, causing it to shift into neutral. Degraded or loose O-rings can also cause this problem. Trucks that have difficulty shifting to or from specific gears often suffer from the failure of the solenoids in the transmission that move the shift valves in the transmission valve body. These solenoids are especially prone to fail in the 45RFE transmission.