I can't speak to the Jeep but I do have some experience with the 700R4/4L60/4L60e transmissions. I've repaired and rebuilt my share during my career as a tech in GM dealerships. Here's my short simple recommendation: Keep it out of the overdrive position at all times except for light highway cruising. Do this and you may see some fantastic service out of these gear boxes.
Here's the long version. The torque converter clutch (tcc) circuit is not fed by its own dedicated circuit off the pump. It is fed off of the lubrication circuit. When the tcc is locked, the lube circuit has no leaks other than the normal pressure loses as fluid finds its way past the bushings, gears, and the rest of the geartrain. When the converter is unlocked, fluid directed to the tcc circuit in 2nd, 3rd, and 4th gears is exhausted through the de-energized tcc solenoid. When engine r.p.m.s are high, as in 2nd and 3rd gears, the pump creates enough fluid flow to overcome the open tcc solenoid as well as keep everything else lubricated.
Things get a bit crazy towing in 4th. Engine rpm is down so the pump output is down. Since your towing the vehicle is typically under load. The converter unlocks and it the transmission stays in 4th, your lube circuit is under performing. The fluid gets hot, the overall line pressure goes down because of the leak and the low pump output, exactly opposite of what you need while towing. Let your imagination tell you what happens in this high load / low lube condition.
If you could monitor tcc lock-up and maintain lock-up in 4th, you could tow in 4th. I can't imagine how fast you would be going to accomplish this. And you have a trailer at this speed? Not me.
For what its worth, I maintain my own personal fleet of vehicles, most with overdrive automatics. I have examples with 150k and 190k miles with original gearboxes. These vehicles never see overdrive unless they are unloaded and on the freeway.
Hope this helps.
Here's the long version. The torque converter clutch (tcc) circuit is not fed by its own dedicated circuit off the pump. It is fed off of the lubrication circuit. When the tcc is locked, the lube circuit has no leaks other than the normal pressure loses as fluid finds its way past the bushings, gears, and the rest of the geartrain. When the converter is unlocked, fluid directed to the tcc circuit in 2nd, 3rd, and 4th gears is exhausted through the de-energized tcc solenoid. When engine r.p.m.s are high, as in 2nd and 3rd gears, the pump creates enough fluid flow to overcome the open tcc solenoid as well as keep everything else lubricated.
Things get a bit crazy towing in 4th. Engine rpm is down so the pump output is down. Since your towing the vehicle is typically under load. The converter unlocks and it the transmission stays in 4th, your lube circuit is under performing. The fluid gets hot, the overall line pressure goes down because of the leak and the low pump output, exactly opposite of what you need while towing. Let your imagination tell you what happens in this high load / low lube condition.
If you could monitor tcc lock-up and maintain lock-up in 4th, you could tow in 4th. I can't imagine how fast you would be going to accomplish this. And you have a trailer at this speed? Not me.
For what its worth, I maintain my own personal fleet of vehicles, most with overdrive automatics. I have examples with 150k and 190k miles with original gearboxes. These vehicles never see overdrive unless they are unloaded and on the freeway.
Hope this helps.
