Supplemental Transmission Cooler?

[Bob662]

A couple of RV friends have suggested I need to add another transmission oil cooler to my tow vehicle. What do you suggest? Here are my facts:

Trailer is 25' FC. TV is F-150, 3.5L, 3.55 axle, Supercrew. It already has a transmission cooler that's about 2 feet long and 3" high. This appears to be the common size cooler that's currently on F-150's with the max. towing package.

So will I need a supplemental cooler, or perhaps a bigger one to replace the existing xmission cooler?

(Edited to add: My truck does have a transmission oil temperature gauge.)

[Echelon73]

Does your truck have a setting in the display to show you transmission temperature? If so, then just monitor it while you are towing. If the transmission is heating up when you are towing (I would say regularly hitting 200) then add another auxiliary unit. If not, then you should be fine. I would do some research to see what people agree is "too hot" for your transmission fluid in your truck though. 200F is just a number I remember from some past research I did.

[Moflash]

You do not need to upgrade your transmission cooler.

[ROBERT CROSS]

.......FIRST INSTALL....the added capacity will work to control temps.

On our first Burb W/O a OEM Temp gauge....

Bob

[tjdonahoe]

I wouldn't worry about 210 degrees, your engine is that or more, when it gets to 240 degrees just back off for a bit....

[dkottum]

Your friends may be basing their advice on experience towing much less aerodynamic, higher profile trailers than your Airstream. Airstream claims they tow 20% easier than the others.

You will have no issues with the transmission overheating based on our experience with two different 1/2 ton trucks pulling our 25' Airstream all over the country many times. IF you do on some long, steep grade in very hot weather with a strong headwind, just back off the speed a little to greatly reduce the wind resistance.

[Jim Foster]

My transmission guy does not like 200 or higher for any length of time. Hard on original equipment seals.
Mine was going over 200 on hills so I added a Tru-Cool 4590. Never over175 now. Cheap insurance.


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[Andrew T]

Hi Bob

The ZF transmission in the F150 (& many other vehicles) does not generate very much heat because it is designed to have the torque convertor locked up almost always so in effect it generates about the same heat as a manual transmission most of the time. The only time it is unlocked is a very low speeds. You would get it the hottest when backing up a steep hill very slow into a campsite repeatedly or something such as being stuck in the mud.

I would change the fluid every 30-40,000 miles and I don't think you will ever have an issue. I would suggest using the ZF fluid for the transmission. The expert on that is California Transmisison Specialties.

Andrew T

[Bob662]

Thanks to all of you who replied. Your comments are really useful.

This forum rocks!

[PaulnGina]

I like the idea of great filtration and great cooling for the transmission and the engine oil. Extra of both is indeed cheap insurance.

(Thank you, ROBERT CROSS, for reminding me that I need to order that transmission filter kit.)

[Moflash]

Before you rush out and add this additional transmission filter on your newer computer controlled transmission tow vehicle check with a qualified service tech for your make and model.
The transmission you have already has a filtration system and the likelihood of it needing a additional filter is not likely as it is a completely sealed closed loop system.
Automatic transmission fluid is changed at regular mileage intervals due to the lubricating properties of the fluid breaking down over time (miles driven)and not because of dirt and debris forming or entering the system.
In this case you may do more damage than good.Your new vehicle warranty may also be in jeopardy if a transmission issue arises.
The same goes for adding a additional trans cooler.


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[blkmagikca]

Also use a good quality synthetic transmission fluid and have it serviced (power flushed and replace the fluid) every 50,000 miles.

[ROBERTSUNRUS]

Originally Posted by Bob662

A couple of RV friends have suggested I need to add another transmission oil cooler to my tow vehicle. What do you suggest? Here are my facts:

Trailer is 25' FC. TV is F-150, 3.5L, 3.55 axle, Supercrew. It already has a transmission cooler that's about 2 feet long and 3" high. This appears to be the common size cooler that's currently on F-150's with the max. towing package.

So will I need a supplemental cooler, or perhaps a bigger one to replace the existing transmission cooler?

(Edited to add: My truck does have a transmission oil temperature gauge.)

Hi, No, absolutely not, unless you are towing a heavier trailer than your truck was rated for. [then you will have more problems than a added on trans cooler could help with] Your truck was designed to handle the rated specs without any modifications needed. Hitch up, put it in Tow Haul mode, and go.

[Bob662]

I wonder if at least the later model F-150's have a thermostat on the transmission coolers or perhaps the transmissions themselves. Mine seems to run at 190dF, no matter the outside temperature. With a trailer behind it I'd suspect it may creep up some more, but that's yet to be determined.

[ROBERT CROSS]

Originally Posted by Bob662

I wonder if at least the later model F-150's have a thermostat on the transmission coolers or perhaps the transmissions themselves. Mine seems to run at 190dF, no matter the outside temperature. With a trailer behind it I'd suspect it may creep up some more, but that's yet to be determined.

Bob,


Most trans coolers will have a by-pass for cold Weather start-ups, just like engine oil, you want the fluid to warm up as quickly as possible. (start & let idle not recommended, (start,oil pressure=drive.)

190* is fine, critical breakout on our Burb is 275*, limp-mode is around 270* steady for 5min.
Ck your vehicle owners manual......


I'm quite sure the Ford Powertrain Control Module is similar and will engage "limp" to help prevent damage.

Bob