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Discussion Starter #1
Hey everybody,

Mishimoto is starting development of a 3rd Gen 2500/3500 transmission cooler! As some of you may know, we try to be open and transparent with our engineering process and we love to hear your feedback along the way. I'll be updating this thread periodically with our progress on this project and you all will get first notice when the discounted pre-sale starts. In the meantime, feel free to check out our blog and let us know if you have any questions! I'm looking forward to sharing this project with the forums and hearing what everybody thinks.



Thanks!

-Steve
 

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Discussion Starter #2
Hey everybody,

Just a small update. This will be a review / known information for most of you, but some newer owners may find it useful. I hope you enjoy either way and, as always, feel free to let me know if you have any questions. I will be out of the office next week but one of my colleagues should be able to answer for you. The next update should come a little faster as this project moves along!

Thanks,

-Steve


A Cooler for Atlas – Transmission Cooler R&D, Part 1: Stock Review



To be completely honest, I’ve never owned a truck. Apart from Dakar rally trucks, I prefer subtlety and agility over brute force and utility. I’ve also never owned a grizzly bear, but I still respect them. Without trucks, our economy would come to a halt, nothing would ever get built, and my subtle and agile car would be wasting away in the salty air of Baltimore’s port, if it even made it that far.

It may not seem like it when you compare live axles and leaf springs to modern multi-link suspension systems and torque vectoring rear-diffs, but trucks are an impressive feat of engineering. They are capable of completing Herculean amounts of work, and must be robust enough to harness massive amounts of power, without disintegrating along the way. In the case of the 3rd generation Dodge Ram 2500 and 3500, the 5.9L or 6.7L Cummins engines provide up to 650 lb-ft of torque to tow or haul just about anything you could ever need.


This cutaway of an automatic heavy-duty truck transmission shows just how complex these machines are.

The truly impressive part of any powerful truck, however, is not just the engine, but the transmission attached to it. The transmission has the daunting task of taking that 600-plus lb-ft of torque produced by the engine and turning it into useable energy at the wheels. Like Atlas holding up the sky, the transmission is a silent servant that constantly bears the violent forces of the engine. For trucks outfitted with automatic transmissions, a maze of passages and valves guide fluid to operate clutches and planetary gear-sets, translating the engine’s rotational force into forward motion. What’s more impressive is that all that work is made possible by only about four gallons of transmission fluid.

As the transmission churns away, that fluid is squeezed onto clutch disks and crushed by gears. That violent action is necessary to deliver power from the engine to the wheels, but it also generates a dangerous by-product: heat. Automatic transmissions rely heavily on fluid pressure to work and, like an engine’s oil, that fluid is designed to operate within a specific temperature range. Cold fluid doesn’t flow easily, and makes it hard for pumps to move fluid where it needs to be. Hot fluid thins out and the transmission’s pump cannot generate enough pressure to engage the clutch-packs. Even more detrimental, hot transmission fluid no longer provides a cushion for the gears’ teeth, causing them to grind against each other instead of meshing seamlessly.


Here you can see the inlet and outlet port of an internal trans cooler, as well as some of the tube that makes up the cooler itself.

Luckily, most automatic vehicles incorporate a transmission cooler to keep the fluid within the optimal temperature range. Many small car and truck transmission coolers are a simple tube incorporated into the end-tank of the radiator. These coolers are cheap to make and great for light-duty use where the transmission won’t get very hot. For larger trucks used for hauling and towing, an external cooler is a more effective solution. In the case of the Ram 2500 / 3500, the transmission is cooled by an external tube-and-fin heat exchanger, similar in design to the radiator it’s mounted on.


The infamous 3rd Gen Cummins transmission cooler thermostat

The similarities between the engine radiator and the stock transmission cooler don’t end there. Much like the flow through the radiator is controlled by the engine’s thermostat, the transmission cooler also incorporates a thermostat. Housed in a small block at the upper-right portion of the transmission cooler, this thermostat diverts flow from the cooler until the fluid reaches the minimum specified operating temperature. The thermostat prevents the transmission from running with fluid that is too cold, but there’s a hitch.


The housing for the transmission cooler thermostat on our truck was covered in grime and debris.

These aging thermostats have seen many thousands of gallons of transmission fluid in their long lives, and along with that, particulate and sludge from the daily toils of the transmission. Over time, this grime builds up on the thermostat and it fails to move with heat. When this happens, much, if not all the transmission fluid is blocked from reaching the cooler. A failed thermostat would be a pretty mild inconvenience if one could simply replace the thermostat, but that’s not the case. Dodge does not sell the thermostat on its own, so a new transmission cooler is the only full fix. Some owners have gotten away with cleaning the thermostat, but unless you want to add draining the fluid and pulling apart your transmission cooler to your maintenance schedule , the problem is bound to come back.



Aside from stuck thermostats, the seemingly large transmission cooler fitted to the Ram 2500 and 3500 is still not enough for some drivers. For those who live in hot climates or tow heavy trailers up steep grades, transmission temperatures can reach uncomfortable levels quickly. The lack of airflow at lower towing speeds, combined with the constant load placed on the transmission, is a recipe for overheating. Without a bump in fluid volume, the stock transmission cooler just can’t keep up.

Many Ram 2500 and 3500 transmissions have fallen victim to overheating due to thermostat failures and insufficient cooling, but we’re working to save every transmission we can. Our engineer, Dan, is designing a transmission cooler for the third-gen Cummins Ram that will keep your truck cool and reliable for years to come. No more stuck thermostats or stopping on the side of a mountain to let the transmission cool.

Thanks for reading!

-Steve
 

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Just purchased a Derale remote cooler for my '04. I like to delete the Heat Exchangers and forward tube and fin coolers on my 6.7's also.
Is your "new" cooler design going to be more of a "stock" replacement ? Or is the design going to be efficient enough to stand alone ?
 

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Discussion Starter #6
Just purchased a Derale remote cooler for my '04. I like to delete the Heat Exchangers and forward tube and fin coolers on my 6.7's also.
Is your "new" cooler design going to be more of a "stock" replacement ? Or is the design going to be efficient enough to stand alone ?
On my 07.5, the factory only uses the cooler in front of the radiator, so there should be a way to build one that can stand alone.
Sorry for the delayed response! We are looking to make the cooler an upgrade over the stock unit that should provide superior cooling, as opposed to a direct replacement. I should have some more updates soon!

Thanks!

-Steve
 

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Discussion Starter #7
Hey everybody,

Sorry for the long wait, I finally have an update for you and should have another update in the next couple weeks with more detail on this cooler! Check out the update below and let us know what you think!

A Cooler for Atlas – Transmission Cooler R&D, Part 2: Prototype


From the outside, you wouldn’t think that the modern pickup truck is exactly the evolution of Henry Ford’s Model T, under the surface however, you might find that the two are more related than they appear. The Model T was a car, built for the masses, designed to be affordable, approachable, and to get people where they wanted to go.

It didn’t take long for Ford and other manufacturers to realize the potential of an affordable utility vehicle. A vehicle that helped them work, so that they could afford to go places in their car. Pickups have grown to sell almost twice as well as cars since the Model T “Runabout” was introduced in 1925, and it’s hard to find a vehicle that can do as much as a pickup. For all the development that has happened in nearly a century, the pickup could still use some improvement to make it a better workhorse.



One of the most worthwhile improvements, in the case of the 2003-2009 Dodge Ram 2500/3500, lies in the transmission cooler. Pickups have become incredibly powerful vehicles (like supercar powerful), and the loads they haul would astound the original owners of Model T Runabouts. That power and weight puts a massive strain on the truck’s transmission and, as we saw in the last post, the stock transmission cooler often can’t keep up. That’s why we’ve been hard at work building a transmission cooler more suited for the stress your truck goes through.



When we looked at this project last, we knew that the transmission cooler needed to be upgraded, but we didn’t quite know how. The stock cooler is already large, taking up almost all the space between the bumper beam and the rad support. But, “almost all” is not the same as “all,” and there’s room to increase the core size. Adding to the width of the core wouldn’t be a problem, essentially requiring shorter brackets and a rework of the line connections. To add to the height of the cooler, however, a few more complicated adjustments were necessary.

The thermostat block would need to be redesigned to work with our thermostat and fit within the new design. With the core size maximized, the new cooler will have a 159% larger surface area to aid in pulling heat from the fluid passing through the cooler. Surface area is especially important in this case because the transmission cooler is sandwiched between the radiator and intercooler, limiting airflow.



Making the cooler larger was a good start, but, as all the pretty girls in high school told me right before they dumped me, it’s what’s on the inside that really counts. These trucks see some abuse, so our cooler needs to squeeze as much efficiency into the useable space as possible. To do that, we needed to see what was going on inside the stock tube-and-fin cooler. A quick trip to the bandsaw revealed the inner workings of the stock cooler. Inside, we found strutted tubes, which give the core more strength and rigidity. However, we also found that the tubes lacked any turbulators. Given these findings, we knew what needed to be done.



Our cooler will ditch the tube-and-fin construction in favor of a stacked-plate design. While the stacked-plate cooler may look similar to the tube-and-fin cooler, there are a couple key features that differentiate the two. Aside from being stronger thanks to the thick plate walls, the stacked-plate design will also be more efficient. Instead of the fluid flowing along the length of the cooler, our design will rotate the plates 90 degrees to flow the fluid along the vertical axis. This will let us cram more plates into the allotted space.

The plates will also be shorter than if they ran horizontally across the core. That may sound like a detriment to performance, but the shorter length means that every inch of plate is being used to cool fluid and no space is wasted storing already cooled fluid. But, as we pointed out earlier, it’s not just the size of the cooler that matters.

You may have noticed a strange word in the review of the stock cooler internals: “turbulators”. It sounds like a made-up word one would use to convince their significant other that they need to buy more parts, but it’s a very real and important concept in fluid coolers. In a liquid-to-air cooler, the most effective portions of the cooler are those exposed to fresh air. Typically, the front of the cooler is far more effective than the back. As the air flowing over the core heats up, it loses its ability to pull heat from the cooler. That means that fluid touching the front of the tubes is cooled more effectively than fluid touching the back of the tubes.


(Click to Enlarge) This diagram shows how turbulators move fluid across the tube, ensuring that all of it is cooled evenly.

Many coolers employ turbulators to overcome that difference in efficiency. The turbulators move the fluid from the back of the tube to the front as it flows through the cooler. As the fluids moves, more of it is exposed to the effective areas of the tube. Looking at the diagram above, you can see that the fluid in the tubes without turbulators is cool at the front, and hot at the back. On the other hand, the turbulated fins in the lower diagram move the fluid throughout the tube in both directions, cooling more of it.

The stock Ram trans cooler does not have turbulators, so the fluid flows from one side of the core to the other, with only a portion of the fluid ever contacting the front of the tube. Our cooler’s plates will use turbulators to make sure every ounce of fluid is effectively cooled.



With all the planning and designing out of the way, it was time to start putting pen to paper and welder to metal. Measurements and a drawing in hand, our fabricator grabbed his welder and got to work. Before a production sample could be started, a prototype was needed to verify that our design would fit and that the mounting brackets were spot on. To create that prototype, u-channel aluminum bars were welded together to represent the outer perimeter of the cooler.



On the ends of the prototype, brackets were measured out and welded solidly in place. Once the welds had cooled, we bolted the massive aluminum box to the truck. The proof of concept was complete, and we had what we needed to move forward with production samples. Our drafters drew up the final designs and sent them off to manufacturing. All we could do now was wait.



Thanks for reading,

-Steve
 

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Discussion Starter #8
Hey everybody,

Just a heads up that I will be out of the office until Monday. I hope everybody in the US has a great Thanksgiving!

Feel free to ask any questions, I'll be getting back to them first thing Monday morning!

-Steve
 

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I’m actually looking at getting one of your intercoolers and might as well replace my transmission coolers while it’s off.

I haven’t seen anything on this with a release date? I only see universal coolers.
 

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Discussion Starter #10
I’m actually looking at getting one of your intercoolers and might as well replace my transmission coolers while it’s off.

I haven’t seen anything on this with a release date? I only see universal coolers.
Hi!

We're looking at releasing this trans cooler in late spring or early summer of this year. There will be a discounted pre-sale shortly before that though, so keep an eye out here for an announcement!

Thanks,

-Steve
 

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Hi!

We're looking at releasing this trans cooler in late spring or early summer of this year. There will be a discounted pre-sale shortly before that though, so keep an eye out here for an announcement!

Thanks,

-Steve

Buy a intercooler kit and get the transmission cooler free ? Lol


What’s the price looking like ?
 

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Discussion Starter #12
Buy a intercooler kit and get the transmission cooler free ? Lol


What’s the price looking like ?
Haha, I'm not sure my bosses would go for that, but the pre-sale discount will be pretty substantial :grin2: I would also suggest doing a quick Google for MMINT-RAM-03 (or MMINT-RAM-03K for the intercooler and pipe kit), as our distributors will be able to get you the best pricing for the intercooler. :thumbsup:

Since we're still finishing up development, we haven't quite nailed down a price yet. Once we get closer to the end of development, we should have a better idea of cost.

Thanks!

-Steve
 

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I looked for yalls vender forum and didn’t see anything on this posted. Could you update this post when the pre sale comes out I’ll pick one up to review/test.
 
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Discussion Starter #14
I looked for yalls vender forum and didn’t see anything on this posted. Could you update this post when the pre sale comes out I’ll pick one up to review/test.
We definitely will! I should have an update for you all in the next week or so.

Thanks!

-Steve
 

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Discussion Starter #15
Hey guys,

Updates came sooner than expected :) Check it out below and let me know what you think!



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


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,

-Steve
 

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I'll purchasing one of these the day they are available!
 

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I'm on board. Buying one when realeased.
 
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