Biopete, the aux tranny cooler won't need the fan.You can have your AC and a tranny cooler. The tranny cooler may have to be mounted out in front of the MBZ aux fan, though. Pick a cooler you like, cut a piece of cardboard to the dimensions of the cooler, and see what fits where, and what you will need to mount it.

You should not need a fan. When it's working hard (the tranny) you should be moving fast enough for good airflow.

Get a stack-plate cooler. They have much more cooling per square inch of cooler. BTW, a transmission makes the most heat when it is not moving or barely moving. Stopping, starting and backing up make the most heat. Just ask any RV owner.

a stack a plate is, but i dont believe that it is true that trannys make the most heat when sitting still and jockying around.

they get fried under highway conditions. the max heat is while driving down the highway pushing a lot of air around the boxy shapes of the rv. if you are pulling a small trailer like a flat bed you prob dont need an aux cooler. but they never will hurt you unless the lines leak and you lose all fluid.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Heat depends on the slip ratio of the torque converter, any time there is less/more that 1 to 1 between the engine and input shaft. Lockup converters reduce heat considerably.

The percentage of slip reduces the higher the rpm's go, up to about 97% of output rpm. Loose converters like street/strip with higher stall speed of 2500 rpm or so will heat up very quickly at speeds below stall speed......up to a point....

FWIW...
I mounted an a/c condenser from a '83 Mercedes diesel under a VW Westy with an older style air cooled engine automatic..(coupled to a 1.8 ltr 1983 GTi motor)..the one's with the vaned torque converter........before cooler fitted, temp's got over 300 F...after, they stayed below 160 F...quite a lot of heat rejection and mounted under the van with no aux' fan...just relied on forward air flow. This was oil pan measured temperatures on the hiway.

This combo had been in use since 1997 up to 2004 when I changed it to a rad' located cooler, because he ran over construction equipment and tore the condenser up..


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[http://languageandgrammar.com/2008/01/14/youve-got-problems-not-issues/ ]

"A liberal is someone who feels they owe a great debt to their fellow man, which debt he proposes to pay off with your money."

well, i installed the temp gauge a few weeks ago in the left tranny line. The right one runs right along the muffler so i did not want to go there. Also, I could shoot the wire up directly up and through a grommet in the firewall. I bet it is the return line but I am after relative temps anyway. Also it may be better to be in the return line to measure how well the transmission cooler is working as that is really the only varaible i can control.

Installalation was easy and only one hitch with this B&N unit -- the 3/8 T does not fit the tranny line. I'm guessing it is 10mm or something but I measured first with a tape measure and read "3/8" . So a quick hack was to use rubber, 3/8 copper tubing, and 4 hose clamps

I have not towed any load yet but sofar what the gauge tells me is :

If it is cool outside, it takes a long time - 30 minutes to hour- to heat up.
It definitely heats up faster the faster I drive.
Max I hit was just over 160 F on the highway and it was like 85 outside. Before it never got above 160.
It can take 30 minutes of city driving before it hits 100F.
When i towed a small 7ft trailer empty, it seemed to heat up faster.

I'm gonna tow a load tomorrow and see what it does.




Havent towed anything but an empty 7ft trailer so

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What Would Rudolph Do?
1975 300D, 1975 240D, 1985 300SD, 1997 300D, 2005 E320 , 2006 Toyota Prius

Install the cooler inline with the factory cooler in the radiator. Run from the trans to the external cooler, then from external cooler to factory cooler and then factory cooler to trans. The reason you want the external cooler first, is because the factory cooler also helps then fluid reach operating temp by transferring heat from coolant in the radiator. It also assures that even if the external cooler is "too" efficient, you are not running around with the trans fluid too cold all the time.

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85 300CD
83 300TD
78 240D (daughter)

You will note that I prefaced my comment "with any kind of heat". If you live in my area of the country and do much towing it would be a great investment for overall cooling, not just the tranny cooler. Heat is your biggest enemy when towing. For a 1000# trailer, in winter temps, I agree with Brandon for a one time towing job.

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Sam

84 300SD 350K+ miles ( Blue Belle )

What do you guys think of the idea of cooling fins on the transmission pan? JCWhitney sells these pans in their catalog for large trucks. They claim a measurable temp drop.
I was thinking about the idea of welding on some fins to the pan the next time it came off for a fluid change. Good idea or bad? Welding heat warping is a risk but fins could either be TIG'd on or even braized on. If they fell off, so be it.

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84 300SD 274K
38K miles on flatplate heat exchanger and various diesel/veg blends. prior to that 4K miles on unheated veggie blends with kero and DinoD.

It gets so hot under the car from the heat of the engine dropping out around the tranny that you probably wouldn't pick up much cooling. I could see cooling at ultra high speeds but once the thermostat is open and the car running down the road, the tranny is sitting in a blanket of hot air heh.

The torque converter makes the most heat when moving slow speed forward or backward, not the tranny. Brandon, gimmick, without much merit. That area under most cars is fairly low pressure air. If there were really enough cooling air in the tranny pan area, a rear main seal oil leak, or tranny leak, would manifest itself with oil on the back bumper.

Well, I was just thinking of easy fun mods. Also working on the assumption that you would have the pan off already for another purpose (ie changing fluid) and a 1hr. diversion to do the mods could get you maybe 10deg. less trans temps on the hwy.

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84 300SD 274K
38K miles on flatplate heat exchanger and various diesel/veg blends. prior to that 4K miles on unheated veggie blends with kero and DinoD.

RLeo, mechanical forensic pathology is what I do. When it really needs to stay together, we don't use hose clamps. The probability of failure of both of our methods, occupy different ends of the curve. Hose clamps, been there, done that, got the T-shirt. As always, YMMV.

Agreed...just offering forumites a real-world, alternate 'been there, done that (for 30,000+ miles) and got the t-shirts to wipe the fog off the inside of the windshield' solution.

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Never a dull moment at Berry Hill Farm.