MD3060 Transmission Cooler Needed?

[fo4imtippin]

So ill be pulling my radiator and intercooler soon and while its torn apart, ill be replacing waterpump, torn belts, timing cover gasket, etc..


So my hoses from transmission/radiator heat exchanger are leaking and im going to drain the fluids/ replace filter and have new hoses made.


Firstly i have a cummins 24v 5.9 with a MD3060. Current fluid is dexron III. I have 141k on the drivetrain now. Its a short 28fter that weighs 17,500lb with full fuel tank. Hard to estimate what my finished build will be, but im expecting between 5-10k more payload (dirtbikes, 125gallons of water, additional 60 gallons of fuel, etc). I also plan to flat tow a 5000lb jeep when i'm done.


That said, i drove 2000 miles and up two steep mountain grades (Guadalupe Pass) and the engine temp and transmission temp never moved off 186. The ambient temps the whole time were between 30-50 the whole trip, and i wasn't running the air conditioner compressor.


So im looking for feedback on those with this transmission as if any of you have or havent added an additional cooler. Im thinking that with the lockup torque converter, that it doesn't have the same heating issues that the AT545 has.


If i were to add one, I would keep the current heat exchanger in the loop, but add a derale thermostat

https://derale.com/product-footer/fl...unt-kit-detail
And i was looking at the below oil cooler.
https://derale.com/product-footer/fl...t/13870-detail
I have room in front of my intercooler, but not sure if its worth impeding the flow, or try to mount it down by my air intake or somewhere by the steps (not oriented toward the wind).


Can anyone help my budget with advice? Should i spend $500 more dollars to add this, or wait until i drive it a bit and add it if i don't like the heat?


Should i spend the extra money to switch my fluid from dexron III to Transynd to handle more heat instead? The dexron III i found is at Tractor Supply. Has anyone used this? Im hesitant since GM stopped licensing the name. The RV forums are all about that Transynd.
https://www.tractorsupply.com/tsc/pr...l?cm_vc=-10005


I need 5 gallons for a drain and refill (and might need a bit more since im changing hoses) so 5 gallon of transynd is about $200 and 6 gallons of Dex 3 is $120.

[2mchprssr]

you could always just run the cooler flat under the bus with a spal fan on it blowing down. i know it sounds as if there wouldnt be sufficient flow but many racers do this with secondary coolers and it works great. personally i wouldnt want to increase my intake temps and lower the efficiency of 2 coolers just to help out one.

[cadillackid]

Originally Posted by 2mchprssr

you could always just run the cooler flat under the bus with a spal fan on it blowing down. i know it sounds as if there wouldnt be sufficient flow but many racers do this with secondary coolers and it works great. personally i wouldnt want to increase my intake temps and lower the efficiency of 2 coolers just to help out one.

I second the thought of aux coolers being remote.. you also have a lot better control of warming up the trans fluid as well.. the aux cooler wont cool much when its fan is off and the trans is cold.. but a Tstat can turn the fan on when the trans isa warm enough to need it.



I run transynd in my Allison 1000 (only fluid its ever had.. my trans was new and dry when i started).. its still as clear and red as the day I poured it in 4 and a half years ago.



I run dex III in my allison 643.. I got that trans new and dry also .. that fluid is still pretty red and clear but can see it beginning to get a darker red which is the time I normally change it.. that was about 2 and a half years ago..



Ive been changign the external spin-on filters in both yearly.



the dex will get changed this spring but the transynd will stay.. both transmissions are running on stock coolers..