2000 Ford Super Duty, 7.3L Turbo Diesel, 4 Spd Automatic, Crew Cab, 87K miles

Need some input on a transmission question. I pull a 10,000 lb fifth wheel and monitor transmission oil temp (after market gauge on column pod). It typically runs at 165 when running on flat land. This last time it was running closer to 180, and when I was going up a grade in 3rd gear it went up to 200. At one point it hit 210, and that's when I pulled over, put it in Neutral, and let the engine run at 1200 rpm. Temp "coasted" up to 230, then after about 20-30 minutes it dropped back down to 190. For the rest of the grade I dropped into 2nd gear when the temp started to rise and it never got above 210.

Driving home I monitored the temp on the flat land, and again it was around 180. Outside temp was around 85.

Does this sound right? Should I be concerned about the transmission? Seems like it shouldn't be as high pulling 10,000. It should be able to pull more than that, so this should be fairly light weight.

I went by the transmission shop that has serviced it, and the owner said I shouldn't be concerned. If I wanted to do something preventive I should look at having the radiator (water, not transmission) cleaned out, not just flushed. The transmission uses the radiator for part of the transmission cooling, and if it is not flowing freely that could impact transmission oil cooling. Does this make sense??

I appreciate your input. Any other forum(s) that I should consider asking these questions?

 

yes it does, make sure you have a good radiator. But lets go a set further. You need a tranmission radiator too. Put one of those on there and you will get those temps inline.

I have a brother in law in AZ and because it gets over a 100 deg there he even put a ele fan on his to keep the temps down.

 

An auxiliary cooler is the way to go.
IIRC the 6.0 cooler is alot larger and a direct replacement.

 

Those temperatures are where the trans was designed to operate. It's normal.

At 220F you need to be watching the gauge carefully. You can go to 250F, but not for more than 1/2 hour. That's Ford's spec on trans temp.

 

thanks to those who have provided answers so far.

 

thanks for input Mark. I'm old school, where 230 is the limit. Soon after that the trans becomes toast.

 

I'm from the more knowledgeable school where a trans can run well above 250F without ANY damage. I've tested that many times, with a teardown after the high temps to see what was damaged. I never found any.