Hi Randy: Over drive or not, if you stop the cause of what kills the tranny you can do as you like. What kills all transmissions is heat! That heat is built up because the tranny slips when under load. To stop it from overheating there are a couple of things that will help. One - is to install an aluminum fin deep oil pan, second - you can add an extra oil cooler in front (the bigger the better). third there are a lot of after market outlets that make heavy duty torque converters and control units that will raise the line pressure to make the clutches hold better. or four - You can go crazy and replace the trans with a Suncoast trans. Your best bet is to keep an eye on it and smell the oil on a regular time frame, if it starts to smell burnt? your over working it and need to take some action to solve the problem. Happy trucking Mike OB