Transmission temps while towing up grades
Fleet Mechanic
Joined: May 2011
Posts: 1,866
Likes: 84
From: Rainier OR
My understanding is that the ford superduty transmissions sence 2003 all have thermostats that keep the transmissions above 190 deg F.
I believe it is for less internal drag so better MPGs
I believe it is for less internal drag so better MPGs
Mountain Pass
Joined: Dec 2018
Posts: 193
Likes: 15
From: Fort Collins
240+ oil temp, 230+ coolant and 225+ trans up the I70 with 7,500lb trailer a week ago for me. Fan kicked into full on "airplane mode" when I noticed the oil temp over the 240+ threshold. Up and over the top at 11,000ft, I watched the coolant temp drop down to 176...the fan works!
Elder User
Joined: Aug 2017
Posts: 624
Likes: 2
We've ascended multiple mountain passes in the Western US, British Columbia, and Alberta. Our trailer is 11k GVW. I've seen trans temps in the low 230 range, at which point the auxillary fan kicked on for a minute or two. Truck seems fine. No issues at all.
Cargo Master
Joined: Jan 2017
Posts: 2,254
Likes: 563
must be some reasoning to the high temps. mines not a ford but empty it stays exactly at 170, no matter the condition. up hill or aganst the wind makes no difference. thats the design temp from what the book said. engine and oil is always 215 probly for emmisions
Laughing Gas
Joined: Oct 2018
Posts: 767
Likes: 78
From: NC
I've had the engine heat up coming down grades as well - I guess the engine braking. Nothing extreme for me since I only have a 5,000 lb or so truck camper, but almost the same temperature change as going up, maybe a little less. It likes to ride in 3rd gear, when I'm going down about 35-45 mph. I don't like to haul **** downhill with a top heavy truck camper on. Down hill usually coincides with lots of twists and turns.
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Hotshot
Joined: Oct 2015
Posts: 19,733
Likes: 12,875
From: Wyoming
I don't think the temperature of my engine has raised any red/yellow flags when going down hill. The transmission on the other hand, can indeed overheat going down hill. I haven't had it do that but I could see it happening if the load is super heavy and you're going too fast.
Senior User
Joined: Mar 2019
Posts: 486
Likes: 8
From: Salt Lake City
I pull a large fifth wheel here in Utah. 44' - 18K lbs. Towed today actually. I run anywhere from 210 to 234 degrees regularly.
It's never gone over 234 degrees though. I'm thinking the fan comes on and it usually drops a few degrees.
2019 F350 6.7 SRW 3.55 Gears.
It's never gone over 234 degrees though. I'm thinking the fan comes on and it usually drops a few degrees.
2019 F350 6.7 SRW 3.55 Gears.
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