There's an external thermostat for the tranny fluid on the '04 and up trucks that controls the flow of fluid to the cooler...does anyone happen to know the temperature of the thermostat, like when it starts to open?

 

Well, I think I'm gonna have to break down and get one. I'll throw it in a pot of water and see when it opens. My first winter in a location that actually has 'winter' and my truck (tranny actually) is definitely running a little different. That big *** tranny cooler is now making it too cool...the '03 and older trucks don't have the thermostat like the '04 and up. I could also easily just bypass the cooler completely for winter since I have AN fittings, but what a hassle.

 

why not put cardboard on the cooler and restrict airflow? See truckers do this on their grilles all the time

FWIW: ford manuals indicate it is a "Fluid cooler bypass valve" located just outside of the trans, and nothing else for its operation :o

 

I thought about the cardboard, but I could do the thermostat and forget about it. I don't think the cardboard would be super effective given the surface area of my cooler. May try it though. Thanks for the reminder.

Yes, fluid cooler bypass valve controlled by temperature. When it's (the fluid) is too cold, fluid leaves the tranny, travels the six inches or so to this "bypass" valve and does exactly that...bypasses the cooler and makes a literal u-turn straight back to the tranny. As the fluid warms, it opens and begins to flow through the cooler.

I already have the fittings I need and the thermostat is only around $30-40...I've already done the homework on this...and then I'd be good to go from now on and not have to worry about cardboard each winter.

I know all I need to know about it...except for what temp is start to operate. Not really part of my decision base, just curious so I have an idea of what to keep an eye on for fluid temps.

 

you could let the truck warm up and idle, and use a pyrometer and watch real time what the temps are and see when it opens

 

Well, I ordered one...$40. So even if it doesn't work out it wont be a total loss. Dealer had zero intel on the operating specifics...shocker, I know. If anyone cares, I'll post up when I get it installed.

 

ive got the same information the dealer has, so i could have told you that they wouldnt know anything, unless they have a tech there that has actually "tested" the open temp...

 

Derale 13011 - Derale Fluid Control Thermostats



Recommended for engines and transmissions. As the fluid temperatures exceed 180°F the thermostatic valve closes, allowing 95% flow through the oil cooler. At temps. below 180°F the valve is open, with 90% of the oil bypassing the cooler. The remaining 10% of the oil flows through the cooler, maintaining constant system pressure, preventing air pockets and eliminating cold oil shock.

Bypasses cooler at 180°F
Provides quicker warm-up temps
Perfect for cold weather climates
Can be rotated 180° to switch flow direction
Flows up to 20 Gallons per minute
Rated up to 200psi
Standard Series

Ultra bright finish
New Billet style design
Kit Includes brass fittings & hose clamps

Premium Series

Black Powdercoated finish
New Billet style design

 

Thanks Fifty...but extremely familiar with that thermostat. There's two or three manufacturers out there making this one or one very similar to it. However, while I do need a thermostat because of where I live in the winter and my big F250 cooler, I don't know of anyone that want's a 180 thermostat for a tranny...I surely don't.

And trust me, I've searched...no one has one of this style cooler than 180. If you could get this around 120, IMHO that would be just about right.

 

I wonder if you call Derale, they can make something for you. I don't know. Just off the top of my head. I've heard that Derale does do some custom applications.

 

yah 180 is on the warm side to start cooling it

 

Yep...come summer time towing you'd be waaaaaaaaaaaay behind the power curve if you didn't even start sending fluid through the cooler until 180. I don't want my tranny above 180 at any time, much less just starting to think about maintaining at that temp.

 

So I looked under mine today. Is this the factory thermostat unit? They probably are rated above 180, since the aftermarket ones are at 180.

 

Yep, that's it...and I will guarantee you that thing is not 180*!!! You'll know here in couple days cause like I said, first thing I'm gonna do is throw it in a pot of water and see when it opens. Wanna put a beer on it?? I'm guessing somewhere around 90-100.

Why 90-100?? Because the 75 has something that supposedly prevents the converter from locking up until there is some heat in the tranny. That temp is supposedly around 95*.

 

I wonder why Derale would make their's for 180 degree. There has got to be a reason.