A Cooler for Atlas - Transmission Cooler R&D, Part 3: Prototype - Continued

A Cooler for Atlas - Transmission Cooler R&D, Part 3: Prototype - Continued

This 2003-2009 Dodge Ram 5.9L/6.7L Cummins Transmission Cooler is now available! Click here to check it out!

As our volunteer truck rolled into the shop, Dan began gathering his tools for a short, and ultimately rewarding, install. Removing the intercooler was second nature to him and before long, the stock transmission cooler was sitting next to its former home. Our much larger, much better-looking replacement took up residence in the truck with only two bolts. After months of work, the test fit was complete.


Before we could begin testing, there were still a few final details to be worked out. You might notice that the lines fitted to our cooler are not the stock lines, and there's a good reason for that. The stock lines for the 2003-09 Ram utilize a quick-disconnect style fitting at the cooler. After 14 years of water, dirt and road salt, those quick-disconnect fittings were more like slow, painful, frustrating-disconnect fittings.

After spending hours soaking our first volunteer truck's fittings in various rust-dissolving sprays, we took to the forums to find that we weren't the only ones with this issue. Many customers either cut their stock lines behind the fittings, adding straight transmission cooler hose to connect to the cooler, or replaced the entire line with standard hose and clamps. Since this issue was so common among owners of these trucks, we figured we'd save you the struggle of trying to pry your stock fittings off and cut right to the chase, literally.


Instead of utilizing the factory style quick-disconnect fittings, our cooler features hose barbs designed to securely hold standard transmission cooler line with hose clamps. For the other end of the lines, we'll be providing stainless steel barbed fittings so that you can cut the quick-disconnect fitting off the line and connect our lines without destroying your hands trying to remove them from the cooler. If you ever want to go back to stock, the factory cooler will mate up to the cut lines with hose clamps without a problem. We'll also be including pre-formed lines that snake around the intercooler flanges, that way you don't ever have to worry about a kinked line preventing flow to the cooler.


While we were on the forums, we also received some feedback from Ram owners about the thermostat that's integrated into the stock transmission cooler. The stock thermostat tends to fail with age. When that happens, the transmission fluid travels in a loop around the cooler, bypassing the cooling fins and overheating the transmission. Unfortunately, the stock thermostat itself is not available to buy on its own. You either buy a new cooler or find a way to make the failed thermostat work.


Because of that all-to-common failure many owners opted to install coolers without any thermostat. However, Rams in colder climates might need the thermostat to help the transmission warm up to operating temperature. That left us somewhere in the middle. Half of our audience wanted a thermostat, the other half did not.


So, to satisfy both, we needed to find a way to allow the cooler to work with or without a thermostat. Dan designed a housing that could incorporate our thermostat and devised a block-off that can replace the thermostat and keep the system in non-bypass mode. For our testing, we used the water jet cutter to slice out a few pieces of steel that mimics the thermostat in the open (non-bypass) position and Mike welded them together. The final form of this piece will be CNC-machined for a seamless fit. The access port for the thermostat is also on top of the transmission cooler. This positioning will allow you to swap the thermostat out without removing or draining cooler.


After all the design time, welding, prototyping, and fitting, we were more than anxious to test the cooler and see if all our work would pay off. Keep an eye out for the next post and, as always, let us know what you think.

Thanks for reading,