HD transmission cooler
 

Alright so my brother inlaw just put a rebuilt tranny in his truck and before they go a tow anything we're going to make sure that heat doesn't kill the tranny.

So i've done some research and I think this is what were going to do. Install an underbed mount cooler, Flex-a-lite #45951, and have the fluid go through this cooler then to the heat exchanger then to the little cooler by radiator then back to the tranny.

A couple questions, Is this the best routing for the fluid? This particular cooler has 1/2" NPT connections and its my understanding that the truck, 92, has 5/8" lines. So is 1/2" NPT the same ID as the 5/8" lines? 1/2" NPT seems like the biggest connections I can find so it must be big enough right?

Also has anybody managed to mount a cooler infront of the A/C condensor and if so which one? I found someone used this one, B&M #70274, and from measuring I think it would work.

Which setup would work better for towing in the mountains? Are there any other setups i'm missing?

Also for a gauge where do you want to measure the temperature coming out of the tranny or going in? Or in the pan?

Thanks, Aaron

transmission cooler
 

I mounted about a 12" X 18" cooler behind my radiator and I am told I reduce the cooling effeciveness by 40 percent. My plow frame got in the way of mounting in front of the air conditioning radiator. I like the idea of an underbed cooler with an electric fan off a small car with the tempurature sensor turning the fan on when the fluid gets hot. I think I will change mine next summer. I don't like the thought of all the restriction of air flow past the primary radiator.

I think that is the one I have with a fan mounted under the bed and I have mine routed so the fluid goes through the factory cooler and before it goes back into the transmission it goes through the Flexolite cooler last.Average temperature last summer pulling 10K was 150*and on a long hill it would get to 185*.Before I had the cooler it would peg the gage at 250*so I don't know how hot it got.All I am going to do for winter is wrap it up in plastic to keep the salt out and pull the fuse on the fan.

ROUTING: The routing you propose is the same as Dodge used when they put a Superduty cooler under the bed.

PIPE SIZE: The piping that runs from the transmission to the heat exchanger on the passenger side of the block (automatics only) and to the cooler mounted over the radiator is 1/2" OD. I just went into the garage and measured it. The ID of the pipe is a little over 3/8".

NPT: The 1/2" NPT does refer to the inside diameter of the fitting. Don't get confused when you measure its thread diameter and find it around 3/4".

There are other plumbing fitting sizes used in cars, mainly performance cars, called "AN" fittings. They're supposed to leak less & require no teflon tape or other assistance. I mention this just in case you want to really research this area. The Flex-a-lite ought to do fine.

DBF

Thanks for your help guys.

So what is the O/D of the metal lines, or what size rubber line would I need to slip over the existing metal lines?

thanks, Aaron