Originally Posted by Bob4x4
Trans temps will be higher in od with an auto or manual.The hd trucks will do just fine towing in od
This statement simply is not true. The torque converter slip is what builds heat. In OD typically the converter will be locked and therefore build LESS heat. However most manufactures do recommend not towing in OD because typical OD band clutch and torque converter lock up clutch are small and can easily be slipped and burnt when towing. Newer HD trucks are built to handle the additional stresses a d can easy handle it. Typical rule of thumb is if you have an older 4 speed trans in a non HD truck you should be cautious towing in OD you still can but you don't want the trans going in and out of OD each time this happens you build heat on the weaker smaller clutch packs that can burn or slip much easier than the larger lower gear packs.