I just had a rebuilt transmission installed. automatic, 2001 quad cab, 2 wd, ..I am looking at a 5th wheel camper in the 13000 lb range. I want to make transmission last so was wondering if it is a good idea to leave in over drive at highway speeds? I have pulled a loaded 24 ft cargo trailer a few times and was told as long as it stays in o/d it would be alright for the transmission. Any thoughts?

 

Any auto I have ever owned and towed with got an oversized trans cooler mounted ahead of everything else....O/D seems like a heat generator to me, but I have a 6 speed for towing....,

 

Definitely agree on the cooler. From a practical perspective you simply can't cool the transmission fluid too much, so the biggest cooler you can make fit would be a wise investment.

That said, the transmission on your 2001 has a lockup torque converter, which means that when you're up at highway speeds in OD, the torque converter will be locked up, and fluid temps won't get too bad. Still, it'll be putting quite a load on the lockup clutch, so it would be wise to disengage OD. What kind of gears do you have? 4.10 or 3.54?

 

Question. Is your transmission still stock? If your answer is yes you have a 47re that came with the truck. Your total combine weigh truck and trailer is 19000. From what you said in your post your overloaded. You will have transmission issues unless you did some mods on it. I would address this issue. I have a 4.10 and 47 re . I only tow with my trailer with OD on freeways with no grades. At 65 mph my rpm is 2000. Good luck.

 

OD on the flat lands is fine. The key is watching your boost pressure and exhaust temp. Those are your "too much load for OD" clues. As long as booth are low, you're OK. If both start climbing, take it out of OD.