Trans cooler hookup...

[AndrewKing]

HI All,



I recently bought a 1989 d250. I will be using it to tow a landscape trailer (about 3500 lbs total weight) ... I want to hook up an aux. trans cooler but have been debating how to do this... . I have the following 3 options as far as I can see... (I very seldom tow heavy but I may every once in awhile)



1) Output of trans to factory cooler then to aux cooler... . Seems like this approach would act like option #3 below?



2) Output of trans to aux cooler then factory cooler... . seems like this option

would take off a lot of the heat when towing heavy so the factory radiator doesn't have to do double duty cooling the trans and the engine... Only disadvantage I can see with this approach is that the fluid in the transmission pan would always be at the engine temp (which may not be a bad thing) BUT if towing heavy wouldn't this be bad since the fluid would be starting out hot and only get hotter... possibly leading to burnt trans fluid and reduced trans ife?



3) Bypass the factory cooler all together and just use the aux cooler (I have it set up that way on my 1993 truck... . now real reason... that is just how the

trans shop did it... . Only disadvantage that I can see with this set up is if I

sit idling for awhile on a hot day I have seen the trans temp go to 200.

At other times if I keep out of OD the trans temp gauge stays below 100

(well doesn't move off the peg at least)... Oh in the winter as long as I am

moving the trans never comes up to temp... . I hope that isn't too bad on the transmission is it?



Which option would you choose?... . I suppose I could get an electric fan set up to kick in when it did get hot but that would only add cost and complications... . Is it possible to overcool a trans?... .



Thanks

Andrew

 

[KOG]

For towing 3500lbs the best thing would be to leave the thing alone. It has ample cooling capacity to tow a good bit more than that. I'm not opposed to add on coolers, I have them on everything I own except the CTD.

 

[PToombs]

I just finished with some research on this. I have to add a cooler on my cousins ferd. It's recommended to go to the factory cooler (heat exchanger) then to the aux cooler. The factory will warm it up in the winter. You don't say where you are or how cold it gets. You should add a trans temp gauge just for an idea how hot you are. Then I would see about a cooler. Like KOG said, for 3500 lbs, I'd leave it alone. (except for the gauge)!

 

[Don Tanklage]

he said he has a gauge and most of the time it does not move off of the pin



and to answer your question, yes, that is hard on a trans



that is why you see race cars running on jack stands in the pits... they are warming up the trans fluid, among other things... .

 

[WJones]

I have mine going to the aux cooler first, that way it will disperse more heat before it gets to the heat exchanger. Id think if you ran it after the heat exchanger it would disperse the heat being applied from the coolant in cold situations and adding more heat to the engine cooling system in hot conditions.



Just my 0. 02.

 

[Philip]

Go with option #2.



The trans is designed to operate in the same temp range as the engine. Running a aftermarket cooler after the factory cooler can keep the trans below the temps it was designed to operate at. If your in a colder climate this might cause problems.



Does the cooler your looking at have a fan on it?

 

[AndrewKing]

HI,
Thanks for the inputs so far... . The local trans guy says he would recommend putting it in after the factory cooler... . As far as the cooler I have, it is the tru cool cooler from DTT... . I spoke with Stefan there yesterday and asked him what he thought about the trans cooler setups and if too low a temp could damage a transmission... . he basically led me to believe that the temps the cooler they sell would not damage the trans now mater how it was hooked up. I guess the safest method may be to mount the cooler under the bed and put an aux temp controlled fan on it... . that way the fluid would remain warm enough (since it would be warmed by the engine coolant and not be constantly cooled by the onrushing air by mounting it up front and then the fan could kick on when it did get too hot)... . I hate to admit it but for simplicity and since Stefan thought it wouldn't hurt by running it cool I will most likely just put the cooler up front without adding an electric fan and plumb it after the factory cooler (local trans guy thought this would be best since I could always cover the aux cooler in the winter with a home made shield if I wanted to have a warmer trans... . He thought this would help in the summer too because the radiator would do the initial cool (down to engine temp) and the the aux cooler would lower the temp even more so when the
fluid entered the pan it would have a greater margin of safety against being burnt by the converter since it would be cooler to start with..... Sounded reasonable to me... I also like leaving the factory heat exchanger in because my other truck without the exchanger in will heat the fluid to 200 degrees
when idling in park (after a prolonged idle... . as in I was using the truck to help charge a battery on a piece of heavy equipment in the field).
Thanks for all the input.
Andrew

 

[sdstriper]

Here is a good post on DTT's site about trans cooler mounting in series vs. parallel.



http://www.dieseltrans.com/phpBB/viewtopic.php?t=201&highlight=series