transmission cooler

[rfitzgarrald]

I am looking to add another trans cooler on my truck. It runs 150* w/o the trailer & 175* flat terrain w/trailer. 220* w/trailer pulling the Grapevine (I-5) in 2nd gear, 900* egt's, engine oil temp 225* & 1800 rpm,s. What do any of you recommend?

 

[dan brooks]

Where is your temp sensor at? If its pulling the numbers from the output line 220* really isn't bad for long, steep pulls when you're loaded heavy. The fluid in the output line is right from the converter, and without a lockup converter higher temps can be expected. Swapping in a better converter will make a difference, but not like a lockup would.



If you're seeing 220* in the pan, you really need additional cooling.



I have some pics in my "Reader's Rigs" gallery of my underbed transmission cooler, which basically duplicates the factory "Super Duty" optional cooler using aftermarket parts. Even loaded to 14k pounds, I can make long pulls in 3rd and the temps will hit around 220* or so. I'm measuring the temps right from the converter.

 

[dpuckett]

Some higher RPMs wouldnt hurt, as you are a hair above the factory stall speed. Read- not in the transmission's best efficiency range. I'd think 2200rpm would be better for long hills- get more power through the transmission and not produce as much heat per power transfer. Your engine certainly has room to grow, unless your t-couple is in the pipe, in which case you are probably pushing the limits.



The stock cooler is pitifully small- a tiny deal in the upper left corner of the radiator area. I'd put a bigger one in there if upping your engine RPMs doesnt help.



Third option would be a tighter converter. How much does your trailer weigh? I'd think you'd be able to go faster than 30mph up a 5% grade, even with a stock engine, unless your transmission temp is your limiting factor, which is good on your part.



Daniel

 

[rfitzgarrald]

Dan, my transmission temp sensor's are in both the goes outta & the pan. I can switch between the two. The 220* is coming from the converter & it's about 10*cooler going back in the pan. As you can see in my truck profile I do have a Mag-Hytec dbl. deep pan, that helps. An extra 3-4 qt's of fluid helps too!

I've been looking at the Derale mod#15800 w/fan and mount under the bed. Good choice?

 

[dan brooks]

If you're only seeing 10* difference at the pan, I'd say you need more cooling.



I'm not sure what size tubes the Derale cooler has, so I can't comment on it. The Flex-A-Light model I used has 5/8" tubes, which are the same size or bigger than the factory hard lines. Almost everything else I looked at used smaller tubes and I worried about restricting the flow of the fluid.



One thing to remember is that the fluid goes through the heat exchanger on it's way back to the pan, and if the engine coolant temp is 220* then the transmission temp will be close to the same. I sometimes wonder if those of us in warmer climates need some way to bypass the heat exchanger except during the winter... .

 

[DBF]

Dan, my transmission temp sensor's are in both the goes outta & the pan. I can switch between the two. The 220* is coming from the converter & it's about 10*cooler going back in the pan. As you can see in my truck profile I do have a Mag-Hytec dbl. deep pan, that helps. An extra 3-4 qt's of fluid helps too!

I've been looking at the Derale mod#15800 w/fan and mount under the bed. Good choice?

The Derale 15800 is the one I've added to my cooling loop to compensate for the removal of the heat exchanger (leaking). I added it in line after the Chrylser Superduty under-the-bed cooler but put in on the passenger side under the bed.



I haven't tested it under load at high ambient temps yet.



DBF