Have a question. Client called today, couldn't make it in b'cause the truck stopped working. Their dodge diesel stopped going, automatic tranny would not engage. They were driving down the highway, no load, no trailer. The dashboard lit up that the transmission was hot. They pulled over to let things cool down by idling the truck like the manual stated to do in that situation. After that, they had no transmission, just plain no go. Fluid checks OK so far, but they still need to have the truck tested. They just had to have it towed home. I'm not a dodge owner, but what gives to have this happen. It's below freezing here, the tranny should not overheat on a simple highway trip with no tow load or cargo. The truck is fairly new. Anyone have any experience with this issue? Seemed odd to me.

sounds like a screwup by the computer instead of a real problem with the transmission. I had a dodge van that defaulted to limp home (1st gear only) mode a couple of times. Man that sure put the wife in a good humor.

Or it could be that the transmission failed and that caused the overheating instead of the otherway around.

JWH,
Most times overheating in any situation:-motor-trans-diff etc.. is caused by lack of coolant or lube in this case. Trans fluid is the coolant and the lube and was probably low and caused the overheat lite to come on. Torque converter/trans would be very low on trans oil and give the no go situation.
A leak would be a bit rare on a new vehicle, but would be the most probable cause.. but then again it is a dodge.HA!
Hope this helps,

Ken