That's what I would do, to include re-routing the existing rad lines to bypass the engine radiator. That will keep trans heat out of the engine and provide better heat transfer capacity for the transmision when it needs it the most. Use a good-sized one rated for a heavy duty application and try installing a temp gauge in there somewhere to keep tabs on it. Best solution would be mounted under bed style like the stock under-bed coolers from Dodge, with a thermostatically engaged fan. That way the heat is again, not getting near the engine cooling system as it would mounted up front, will only get the extra air flow when needed, and keeping the system at more consistent operating temperature.

 

What vehicle are we talking about here, the Chevy or the Dodge? If the Chevy, what engine does it got?

 

is there a fan shroud in place? i have seen motors w/o one run fine but increase the load a bit and they overhead like crazy due to not enough air being pulled through the radiator. if there is a fan shroud make sure it is not too big for the fan.

 

Guys we have had to edit out a bunch of stuff and even remove some posts, please respect each other even if you don't agree with each other.

 

The other nice thing about the remote trans cooler is you can put an electric fan on it. Compared to ford and gm diesels, the cummins runs cooler due to no pre-combustion chambers, so I would say it's either a flow issue (water pump or radiator) or the tranny cooler. You might be able to retro a late model dodge tranny cooler up front too. Good luck

 

WildBill it's an 89 Chevy Dually with a 1st Gen 12v Cummin's transplanted by the local Cummings Distributor here called Cummins NW.

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The shroud looks to be the proper shroud for the application. What I mean is that it's size looks very comprable to the size it should be in relation to the fan.

One of the ealier posts asked what the temps were. Well the engine temp was close to redlining at 260.

With the external trans cooler is there a potential of not getting enough heat? I also wondered if the power to weight ration might be an issue in that a stock 1st gen probably makes what 130hp to the rear wheels? If I have the motor tuned up will it work easier pullying the long hills?