The truck I installed the radiator on is a 99.5 F250 AT 4X4 w 7.3 powerstroke. Thats good info to know that the Mishimoto Radiator/Transmission cooler works so well. I was curious as to how well it would work on our trucks. I looked at the Radiator when I installed it and figured I could of used the Transmission cooler portion, I just chose not to. I currently still run the stock external Transmission cooler that the truck came with, but I think I might upgrade to the Mishimoto Transmission Cooler as well. My system runs very efficient now and I don't plan on doing a lot of towing with it anyhow, but I do like the Mishimoto Transmission cooler as well and may even purchase one to install on my truck. I think it's time to swap it out.

 

I think you missed my point. Did your truck originally use the radiator cooler? I believe Ford didn't start using them until 2000 or later.

I don't have the Mishimoto external transmission cooler, I added the Oil to Water lines so my transmission runs through the bottom half of the radiator and the external factory V10 cooler.

Prior to purchase of any more coolers I'd recommend adding the two cooler lines to make it so you can use the OTW cooler within the radiator, this will have the biggest benefit on your transmission cooling package. The hard lines are relatively inexpensive from Ford too.

 

* Correct I got that. Its a gas engine, so I think it might have been built this way OEM due to the lack of the Heavy duty tow package that Ford offered back then. I believe all the Diesels came with External Transmission Coolers. Its part of the Heavy tow package. Some one correct me here if I'm wrong about this. If I recall from my days at Ford, there were differences in the tow packages for gas and diesel trucks. All Diesel come from the Factory with external transmission coolers. On gas engines it was an option. So this in and of itself makes me wonder how much more efficient is it to run the Transmission cooler thru the Radiator as opposed to thru an External cooler.
*Let me try again. Maybe I missed something. My personal truck came with an OEM external transmission cooler from the factory. In my response to you I merely commented on the Mishimoto external Transmission cooler that they also offer as a replacement to the trucks that came with one. A lot of guys that own 7.3's upgrade to the 6.0 transmission cooler, but personally I like the Mishimoto replacement as opposed to the 6.0 option. You could be correct on the efficiency of the Radiator Transmission cooler as it utilizes the coolant flow and air flow to control temps. It makes sense, but I don't have any data to prove it. I'm sure someone here has that info though. Again, the OEM installed an external cooler on all the Diesels, and they are known to tow loads more efficiently than the gas trucks, so out of curiosity, lets see what some one comes up with here on the differences between the 2. I won't research it myself, I don't have that kind of time, and honestly I don't care to, but I'm sure someone has already done this.
On edit; I think I added some information with in my post that was geared more towards the OP/Mark that created some confusion, so I apologize about the mix up.

 

I replaced the water pump earlier last year with the one from the International bus as suggested by @Nicmike I am very happy with the results. Mike had pieced the kit together. But I ordered this kit from Dieselsite as it comes with all the needed pieces all together.

 

You're wrong about this.

From the start of the 1999 model year until mid-2000 there was no radiator cooler in ANY Superduty. There was only an external cooler. Curiously, the largest cooler was on the V10. The diesel cooler was a bit smaller.

Coolers were not specified by what Ford thought the truck would be used for. All coolers were spec'd to keep the temperatures within spec when towing at maximum GCWR. up a certain grade, at a certain outside temperature.

From actual testing, I can tell you that the internal cooler makes a HUGE difference. Ford deleted it in an overzealous push to save money. I can't share actual numbers because that would be wrong and because it's been too many years to remember the details.

The internal cooler is much more efficient because transferring heat from oil to water is MUCH more efficient than from water oil to air.

Edit: Fixed the typo in the last line.

 

And... more efficient than from oil to air too!

 

I stand corrected.

 

When I upgraded to the 6.0 from the tiny little external cooler on my 2000 Ex 7.3 I did not use the internal radiator cooler at all. Should I also have plumbed that in? And if so, in what order? Before or after the external cooler?

 

I have a new radiator with the cooler and installed the 6.0l cooler, I did NOT plumb both together. I plumbed a Derale fluid thermostat between the transmission and cooler, I see towing temps 175*-195*. It takes high ambient temps to push the temps above 185*. If your transmission doesn’t get to a high enough temp 175* for a significant amount of time you don’t burn off any condensation. You don’t want your transmission to stay too cool or get to hot...

 

In a word: Yes.

For optimal transmission cooling performance when towing or hauling or under load, you would want to have the Oil to Water transmission oil cooler plumbed into the cooling circuit.

Ford had to relearn this the hard way. Although it was likely harder on individual truck owners than it was for Ford. Still, when certain folks at Ford decided that they could eliminate the oil to water cooler, they essentially eliminated from consideration the many years of automotive engineering experience Ford already had in their collective metaphorical vault. It isn't like Ford just started building trucks 20 years ago. Ford celebrated their 100th year building vehicles back when the 7.3L diesel was still in current production. My Ford trucks of the 1970's had oil to water transmission coolers. It isn't as if this hadn't already been figured out.

So why bother with OTW coolers, when you already have the largest OTA transmission cooler on the planet? An OTA cooler relies on moving air to transfer heat out of the oil coursing through the thin aluminum plate passages. How much moving air is there in stop and go traffic? How much moving air is there when in reverse, backing a trailer up a driveway? How much moving air is there when starting from a standing stop up Canton Avenue in Pittsburgh PA? (37% grade, perhaps the steepest public street in the western developed world). When pulling a trailer up the Teton Pass out of Jackson Hole, and stuck behind 20 mph gasser gasping for air, how much moving air is available to reject the heat from an unlocked torque converter?

That's where water helps. Water is moving, because the water pump is moving it. And water is more efficient at absorbing heat.

Water is so efficient, that in new Super Duties, having transmissions with more than twice the number of gears, and rated for twice the poundage of trailer pulling... there is NO oil to air transmission cooler at all. Instead, there is only an oil to water cooler.

It looks like this:



So you might say that Ford finally put the right people back in charge of transmission cooling... beginning with Mark... and continuing on the right path more than a decade following his retirement.

Oil to water is where transmission cooling can get done, in forward and reverse, in slow speed or at high speed, agnostic to air flow over an oil cooler, and synergistic with the greater volume of cooling transfer medium available in the cooling system.


Hot out of transmission into OTW first, then out of OTW into OTA second, then out of OTA back to return/sump of transmission. This is how the OEMs do it.

Careful of Derale thermostats. Over the years, various users have reported impediments to return flow. The 4R100 requires 1 gallon per minute return flow through the cooling circuit. This can be tested by temporarily running the return line into a quart container. If it fills in 15 seconds, that would sufficiently verify the 1 gallon per minute flow requirement.

 

For the best trans cooling, yes, you want both coolers.

The correct order is from the front of the trans to the radiator cooler, then to the air to oil cooler, then to the rear of the trans.

 

Thanks for that info Y2KW57. Just what I was looking for.

 

If you wanted to really get fancy you could try that electric fan kit behind the Mishimoto. Mechanical fan clutch is a power sapper and you don't even need fans in the winter.

 

But you sure need the mechanical fan when the truck is working hard. The electric fan won't but it in maximum cooling situations.

 

the cost of an Electrical fan capable of replacing the CFM that the stock fan puts out would be very hight if one even exists that could fit in the space available. I have never seen one anyhow, show us what you had in mind.