One concern of mine about this new transmission was the transmissions temps I was experiencing while not towing as I purchased the truck last November and hadn't had the chance to tow with it yet. Driving down the Interstate in the middle of winter I was seeing temps of 203* @ 80 mph. We finally got to tow our 9,200 lb travel trailer about 70 miles in flat/rolling terrain @ 65 mph. Ambient temp was 87* and I'm happy to say that I never saw the trans temp go over 203*. In fact, sometimes it was below 200*! Very happy how this gas F-250 tows a heavy load in tow/haul mode. BTW, according to the trucks computer, I averaged 9.5 mpg. Very pleased.

 

There is a thermostat in the transmission that keeps it that warm. The transmission is more efficient hot and that is part of the reason you get decent fuel economy.

 

Thanks Mark, as usual your comments are greatly appreciated. I think a lot of us were concerned that we were gonna see a lot higher trans temps while towing than 203*. I'm perfectly happy with the temps I observed. It's the 220-230* temps that I expected to see while towing that would be the concern. Really pleased how the truck performed towing this weight. Now if they could do something about the trans "clunk" that many of us are experiencing that would be the icing on the cake.

 

220-230°F isn't a problem at all for these transmissions.

 

Speaking of transmission's with thermostats, I will relate a story that has a bearing on this thread:

An acquaintance of mine called me recently. He knows I used to own a couple of Aamco transmission centers and currently a new SuperDuty 6.7. He bought a slightly used '17 F350 6.7 (something like 10K miles) to tow his rather nice boat. He recently took the truck in for service and was told by the shop that he should upgrade the transmission cooler since he was towing such a big/heavy boat to the gulf coast regularly. Made sense to him so he popped for the cooler at $350.

He was saying something must be wrong since the transmission temperatures were basically unchanged. He assumed that the shop took his $350 and stiffed him on the cooler and wanted to know what he should do. I had to laugh....

 

Good to know and again thanks.

 

Yep he got taken even though they may have actually installed the extra cooler. I've read somewhere on here that you could put 5 coolers on and not change the operating temp because of the internal thermostat.

 

Yep. They might very well have. Knowing this guy, he's pretty smart but sometimes falls victim to the "too little knowledge and not knowing it" syndrome. He has had a succession of nicer and nicer boats and truck to tow them with. So he bought the '17 SD to replace his previous GM truck. Trying to be smart he was monitoring the transmission temps and noticed they were higher than his old trucks. Asked the shop about it and they told him about needing a cooler. Its very possible that the shop was trying to be legit and just didn't know what the normal temps were for this truck.

 

It would bother me greatly wondering if the new cooler was actually any better than what came from the factory.

the factory coolers are soooo good now that It is hard to improve.

 

The Ford factory coolers are excellent and have been for years. I had a '95 Ford E150 Clubwagon that I towed with all over the US and the factory cooler was more than adequate. Florida in July. West Texas on I-10 in August. It didn't care.

 

If you run that many in series the pressure issue is that you'll likely have NO cooling since no fluid will be pumped through that mess.

 

I agree with the above, he got taken. He may be better off removing the aftermarket unit and going back to the OEM setup. Nothing good can come from this, but it adds the possibility of leaks and increased restriction causing inadequate flow. I've never heard of someone overheating the transmission on a properly-functioning 2008 or newer Super Duty, the cooling systems are outstanding.

 

Did a 2k mile trip this spring from Denver to Grand Junction to Bryce Canyon to Hoover Dam to Grand Canyon to Monument Valley to Pagosa Springs and home to Thornton. Trailer weighed in at 9k lbs.
Plenty of steep grades. Temp maxed once at 210. 207 common. Truck has 20k on it, Changed the fluid and filter when I got back just for "fun". Fluid was bright and clear, no heat smell at all. Very little break in debris on magnet.
Very pleased and now confident. Another strong component in an awesome truck.

 

What I don't get is...with the thermostatically controlled transmission cooling being so effective, why does it take so long after the engine appears to hit operating temp for the trans to also hit operating temp?
Maybe it's due to sensor location? Or?

 

Transmissions warm up much slower than engines do. It also depends on how you drive it. Low load in 4th gear and higher means the converter clutch is applied and since the majority of the heat comes from the torque converter turbine working, with the clutch applied there isn't that much to generate heat.