Transmission Cooler Reccomendations

[Wicked_Sludge]

You can over cool a transmission. You should never eliminate the cooler in the radiator because it is also a fluid heater.

beat me to it. what the stock tranny cooler is designed to do is keep the tranny the same temperature as the engine coolant. your coolant temp is actively controlled via the thermostat, thus your tranny temperature is regulated.

since your stock setup is regulated, having the tranny run at 200* doesnt give you any indication of how much of your cooling capacity is used up. what you should do is hook up your trailer and go for a tow. if your tranny temperature climbs higher then what you experience driving around normally, you know your at or over the limits of your stock system, and are in need of an additional cooler.

i hope that comes out clear

 

[almostclueless]

Dang!!!! New website, and I STILL find myself agreeing with sludge sometimes LOL.

 

[Ozwynn]

lets try this again smart guys ....... raise your hand if you have ever had transmission fluid puking out the front seal in a bronco 2. this can be caused by a few things like the front seal going bad but most of the time it is caused by the engine over heating inturn cooking the transmission fluid wich inturn makes the engine get hotter. the fluid expands and blows the seal. at this point you might as well plan on replacing the heads (because they are cracked) Therostat (because it stuck closed) and a transmission because at this point the bands and clutches have been cast into the deepest hottest parts of transmission hell. a trans cooler with a fan set to run at 175 degrees could have saved this transmission. $189 is cheap insurance for a transmission that costs around $1200... and I have no Idea what a 5r55e costs but I doubt you can replace it for $189. and auxiliary cooling is race and towing proven to keep the transmission in its happy range.

or in the case of my suburban that the temp gauge was stuck on 180 degrees and nobody noticed. it was raining so steam was coming of the truck anyways. it gave no indication it was hot until the transmission started slipping and by this time it was too late. I was towing a around 8000 pounds (rated for 9000) to ann arbor going about 70 mph and the transmission got hot and and started heating up the engine which further cooked the transmission. so yes, in my opinion you can not have too much cooling capacity for an automatic transmission. the closer it stays to 165 degrees the better it runs. Raptor transmission checks all their product in their own trucks before they are shipped and this cooler is proven on a 4L80E pulling 19,000lbs (wieght of their truck and trailer) and it keeps it cool, period

 

[Will]

Well, I didn't make that chart, but TCI transmissions has it on their site as well.

The tranny doesn't need help getting warm. It does that just fine. The thing about the radiator's built-in cooler is that it is fluid-fluid, not fluid-air. Put on a pair of soaking wet oven mits and you'll see how much more efficient fluid-fluid is over the dry mit fluid-air in transfering the heat from a casserole to your hands.

It's important to keep the cooling system in your truck up in order to also keep the tranny cool. But the tranny WILL get hotter than the engine and the engine's cooling system won't adjust for it enough so the factory puts an auxillary cooler on.

I do not think that particular lubricant needs to be hot to function. It's also used in hydraulic systems that don't deal with anything like the power that a transmission in a vehicle does. It's in my Bobcat--the mechanical clutches are bathed in it and a little 3gph pump drives a 1,200psi 2-valve system--and trust me, the lines do not get hot--the pump gets warm and it definately needs lubrication--which the fluid at maybe 120*F (the pump body gets much less warm than our waterheaters output) provides. But if the fluid is used to lube+cool something like an automatic tranny that might have a 200hp load slipping 5% in it, that is 10 hp worth of pure waste heat transfered to the fluid and it will easily boil, break down into deposits, harden and destroy seals and lose it's viscosity wiping out clutches and bands.

I will definately agree that you cannot overcool and automatic tranny.

This is from amsoils site. According to them (and they know nothing about it, i'm certain) you should definately shoot for that 175*F.

 

[krugford]

Also keep in mind that if you have the factory tow package (or maybe it's just the FX4s), it came with a seperate air/fluid cooler mounted in front of the radiator/ condenser. I know this because the lines they ran really get in the way when you want to remove the front license plate "bracket" and replace it with a real bumper....

-krug

 

[Will]

Also keep in mind that if you have the factory tow package (or maybe it's just the FX4s), it came with a seperate air/fluid cooler mounted in front of the radiator/ condenser. I know this because the lines they ran really get in the way when you want to remove the front license plate "bracket" and replace it with a real bumper....

-krug

All RBVs have that auxillary cooler. It's obvious Ford wants the temp below the radiators 195* thermostat setting. The radiator is damn efficient, but it doesn't take the temp down quite far enough.

 

[krugford]

All the new ones have it? When did they start that? I assumed I was special...

 

[Will]

All the old ones have it too.

 

[2manyfords]

IIRC, the factory RBV tranny cooler is down stream from the radiator cooler.

 

[97ranger4x4]

Okay sounds good. I will defenatly hook up a trailer in the next few days and tow it around and see what I can get the tranny up too. I will also look at getting a tranny cooler with the fan built on. The $189 is a little more than I had in mind. I know it is cheap insurance especially with the miles I am starting to get on the truck. I will see if I can find something that maybe isnt quite as hardcore. All of the towing I will do is with a small 4x6 enclosed trailer with about 600lbs of gear in it or a ski boat (but this would only be a short distance 12mi or so)

 

[Wicked_Sludge]

if your only talking about 7-800lbs then i would be surprised if the stock cooler wasnt enough. thats a fraction of the 3,000+lbs your truck is likely rated to tow.

if your looking for something a little less extreme then the cooler posted, look for just a bare cooler (without fan). your radiator fan will still move plenty of air to aid cooling and you can always buy a small fan to add on later should you desire.

 

[Wicked_Sludge]

What? You don't need to heat your radiator.

under normal conditions, the engine coolant warms the tranny fluid...not vica versa.

 

[Capt Jay]

Ya

 

[Ozwynn]

IIRC, the factory RBV tranny cooler is down stream from the radiator cooler.

thats how it works, goes into the radiator cooler and then into the aux. cooler. the above diagram shows the hot fluid going in on the bottom and the cold fluid coming out the top of the of the aux cooler ...... thats backwards, heat rises so you want the cold fluid coming out the bottom.

 

[MAKG]

Some of these diagrams are making me scratch my head.

Conventional crankcase and gear oils generally work fine up to about 350 degrees, not at all coincidentally the peak engine temperature inside crankshaft bearings. ATF is a different lubricant, but it's still an oil and I find it rather hard to stomache that it's so much worse. I think Amsoil is exaggerating. They certainly have a vested interest in doing so. Perhaps a neutral analysis such as from API might be more believable.

As for the transmission temperature charts, there clearly has to be a minimum safe temperature, even if it's nothing more than the pour point of the lubricant (though I'd expect the first problem one would see would be sticky valves in the valve body -- they are steel valves in an aluminum body and will fit tighter when the lubricant is cooler). It's also more than a little weird that the factory would require inappropriate fluid for the operating temperatures.

As for it not being possible to overcool, perhaps that might be true in the summer (though I don't really believe it), it absolutely is possible in extreme cold. Given that you can drive to the Arctic in winter, it can't be ruled out for everyone. It's like saying you don't need antifreeze.