I have a 1999 7.3 F350cc with auto trans. My trailer with toys is about 9,000 lbs. Lots of hills here in the West so I am always going up steep hills where I go camping. I already put a transmission cooler in front of the radiator but still after hauling up a steep hill in 1st or 2nd gear I know it's getting to hot as I can start to smell the oil. I am trying to figure out how to remedy this. Anybody tried to put a transmission cooler under the frame with temperature sensors with fans because its obvious that the one I have now isn't doing the job. I'm afraid I am going to toast my tranny one of these days.

 

Most here use the 6.0 cooler which bolts right in and does the job. Also a radiator with a transmission cooler is recommended, some 99s didn't have that but you can add it. Two oil to air coolers is not recommended, just one good one will do the job.

If you can smell the fluid it might be puking out of the rear seal.

 

Second that opinion- I've got a 6.0 cooler, and just last weekend we went from 2,000 feet up to 9,500 feet hauling a 6,000 lb. + trailer with gear. The only time the trans got above 170 was the last few miles, which was the steepest part of the climb and it maxed out at 190.

 

Running through the radiator cooler and then the 6.0 cooler I never ever ever see more than 170 degrees even in 110 in Phoenix or up 8% grades for 10 miles at 85% throttle doing 75mph towing a high wall 7500 lb travel trailer.

The big 31 row 6.0 cooler should have come stock on these trucks.

 

Are you guys buying used coolers?
If new, your retail source and part number(s)?

 

Yes, I would like to know if you are buying new or used or where is the best place to get the 6.0 cooler.

 

Best to buy new, used is a crap shoot. Especially if you have no history on it. I got a used one on line and it is good but I was just lucky to find an honest seller.

 

I like Amazon, what can I say?

https://www.amazon.com/gp/product/B0...=ATVPDKIKX0DER


A lot of people have run these Dorman branded coolers with no issues I have seen as yet......

 

Yup that's the one I got over a year ago....works great. It's HUGE !!

 

Dorman...made in China?
Does it bolt on using the same points as the original?

 

Another Doorman user here. Bolted right in and no issues at all

 

Well I just ordered the Dorman from Amazon. I looked at all the reviews at Amazon and they were all 4.5 stars or better. I guess I will see. No other parts house (autozone, advanced, Napa) had anything. All were small "add on's" like I already have. We will see how the installation goes. Thanks everyone for the help!!!

 

Here's a good write up on how to. Someone here suggested it's easier to install from the bottom up so I tried it first and it went pretty well. YMMV

https://docs.google.com/viewer?a=v&p...MGM2YzhiYTliZQ

 

I ran in to the same issue with my truck. Put a 6.0 cooler in and it helped....kinda. The issue you are having is that the 4r100 does not lock the torque converter in 1st or 2nd gear, and at those speeds there is not really enough airflow for the 6.0 cooler to do its job.
What I did was put a torque converter lock-up switch in. This will reduce the amount of heat the transmission is generating. I don't recommend shifting with the converter locked up, and at slow speeds you can fall out of the power curve at times, but you can always unlock it to get going again and then lock it back up once you gain a little speed back.

 

Blurple, if a 6.0 cooler did not help that much, something is rottem in Denmark. Or you have a pre ~'99.5 without the trans cooler line in the radiator. Most that I have seen in my truck temp. wise is ~200*, and that is towing a ~ 10K+ trailer in 100+* weather up a 6% grade. I also have a Magnifine filter in line as well (not recomended by some) - but may remove it just for drill anyway.