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Derale Dyno-Cool Tube-Fin Transmission Cooler Kit - Class III - Economy

Derale Dyno-Cool Tube-Fin Transmission Cooler Kit - Class III - Economy

Item # D12903
Our Price: $46.71
Transmission Coolers

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15-1/4" Wide x 7-1/2" tall x 3/4" deep, reliable, all-aluminum tube-and-fin cooler extends the life and improves overall functioning of your vehicle's transmission. Great Prices for the best transmission coolers from Derale. Derale Dyno-Cool Tube-Fin Transmission Cooler Kit - Class III - Economy part number D12903 can be ordered online at or call 1-800-940-8924 for expert service.
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Derale Transmission Coolers - D12903

  • Tube-Fin Cooler
  • Mid-Size Truck
  • SUV
  • Van
  • With 11/32 Inch Hose Barb Inlets
  • 15-1/4W x 7-1/2T x 3/4D Inch
  • Derale
  • Standard Mount

15-1/4" Wide x 7-1/2" tall x 3/4" deep, reliable, all-aluminum tube-and-fin cooler extends the life and improves overall functioning of your vehicle's transmission.


  • Improves functioning and overall performance of transmission
  • Extends life of transmission and prolongs period between necessary fluid changes
  • Cuts down on heat-related failures
  • Agitates fluid with built-in, embossed turbulators for more efficient cooling
  • Constructed of durable, lightweight aluminum
    • Thermal-conductive metal provides excellent transfer of heat
  • Includes:
    • High-temperature, OEM spec hose with stainless steel clamps
    • Nylon mounting rods
    • Insta-dapt radiator adapter
  • Recommended for mid-size cars, trucks and SUVs
  • Imported


  • Inlets: 11/32" hose barb
  • Overall dimensions: 15-1/4" wide x 7-1/2" tall x 3/4" deep
  • Core width: 12-1/4"
  • Distance between inlets: 6-1/4"
  • 1-Year warranty

Note: The Derale Insta-dapt radiator adapter fits most vehicles with 5/16" transmission lines, but not all. In some cases, additional fittings or alteration of the OEM lines or hoses may be required for installation.

Perhaps the simplest type of heat exchanger, the tube-fin effectively cools a variety of automotive systems. The concept is simple: Fluid cools as it travels through the core by transferring heat out to the fins. The fins then provide the surface area necessary for sufficient heat exchange to take place, allowing the heat pulled from the fluid to dissipate into the surrounding air. Quick, easy and effective.


Replaces HH41013

12903 Derale Dyno-Cool Aluminum Tube and Fin Cooler with Installation Kit

Installation Details D12903 Installation instructions

This Product Fits The Following Vehicles

Customer Satisfaction Score:

Customer Reviews

Derale Dyno-Cool Tube-Fin Transmission Cooler Kit - Class III - Economy - D12903

Average Customer Rating:  4.6 out of 5 stars   (130 Customer Reviews)

15-1/4" Wide x 7-1/2" tall x 3/4" deep, reliable, all-aluminum tube-and-fin cooler extends the life and improves overall functioning of your vehicle's transmission.


Great cooler upgrade for my 1997 GMC Yukon! Little delivery damage, but was so easy to bend those fins back to original shape so no worries!
Nice that you had proper dimension measurements online, so it was easy to figure out what kind I can fit in my truck. Complete kit had everything I needed to get it done!
Modified old cooler bracket little bit and that was it. Works great!

Henri L.


It’s working great! Installed transmission temperature gauge also and temp is keeping between 110-130F on any driving conditions. Looks like new, no corrosion any kind, very happy with this one!

2017 Chevrolet Silverado 1500

The products I ordered arrived on time and was great quality. Everything matched up and placed on vehicle same day.Its functional and working great! Cooler temps on my transmission. Thanks etrailer! I'll be ordering some more items soon!

2010 Chevrolet Avalanche

I just installed this on my chevy avalanche.
the bottom brace around in order to mount to.
The hardest part is getting the hoses on the cooler and over the return line.
I ended up getting a 90 deg quick connection coming from the radiator instead of using the one I got from etrailer. This keeps the hose from bending as much.
Also purchase the installation kit with a hose as you will need an extra hose.
After install I wish I would have went with the next bigger unit which is 10 high instead of 7 1/2 as I had plenty of room.


I have always loved etrailer and their service. Once again order another of these coolers. Drop my temp from 240 to 170-190 also remember to order extra hose, the adapter if needed for your vehicle make, mount kits. Love it. Perfect this one is on a 07 GMC Yukon XL always add an extra cooler on your 1500 gmc or chevys they help out so much for them.


Excellent, way better than the WeatherTech rain guards I had on there before.


Hose barely fits on the fittings of the fittings of the cooler. It was very frustrating.

2007 Chevrolet Avalanche

I bought this cooler for my 2007 Chevy avalanche LTZ 4X4 with 5.3 motor. I also bought the adapter the adapter D13035 for my truck as well. It was a quick and easy install. I just got it installed on 2/2/2018 and took the truck for a drive and it has dropped my transmission temp at least 40 degrees. It took me around 40 min to install. Very Happy with this new addition to my truck. FYI if you buy this unit to make it easier i would order an extra Line because the one line will be cutting close to reaching location.


It appears that my transmission temp dropped about 40-60° adding this cooler. The hose was pretty hard to attach to the cooler, even with lubrication. The hose was also to small for my vehicle so I had to source other parts to make it work. I installed it on a 2017 explorer.


Very good product works well. The reason for 3 stars, it's NOT a direct fit as described when I purchased the product. The transmission lines are fitted to the A/C condenser so they had to be cut and needed to buy a flaring tool to flare the cut transmission lines. I look at the product online and now there's a note stating altering OEM lines may be needed. This wasn't there when I purchased it which delayed my install for another day.


All parts were as they were stated. I have not towed my boat for any distance yet to see how well it lowers the temp of my transmission. Idid have to buy some more because I came up about 6" to short.

1994 Volkswagen Eurovan

Lacked one connector for my application.


Just got it in the mail the other day. Fast shipping, never have had an issue. Having it installed right now. Feels like it is well constructed and should do the job. We shall see what happens.

Robb B.


What is the rated towing weight for a 1999 Honda CR-V? Does a trannie cooler install fairly easily on the Honda CR-Vs? What is the most effective mounting location for the finned cooler? How does the addition of a trannie cooler effect the volume of fluid and fluid level reading on the dip stick? Thanks for your time and expertise.

Patrick B.


The towing capacity question is a loaded one. For that, I would refer back to the owners manual. It can vary depending on engine, transmission, drive configuration and more. Furthermore, Honda has some very specific guidelines regarding towing so it's best to defer to them. Installing a trans cooler on a full size truck can be easier because of the extra space, but it is not particularly difficult on any vehicle. We actually have a video of a cooler being installed on a 2006 C-V. We remove the front bumper cover for the video, but you may find you do not need to. (See link). The most effective location will be in front of both the radiator and the A/C condenser. As you move behind each cooling device, the efficiency diminishes. We put ours in front of everything on the 2006 in the video. For fluid capacity, plan on an extra 1/2 quart. Depending on cooler size and construction, it will vary some, but 1/2 qt. is a good rule of thumb.


Put 10k miles on it so far so good. I'm running it on a modified trans behind a 550 horse 6.0


works great for a simple upgrade.







I put the transmission cooler on a 2006 ram 2500 it keeps it 30° cooler than the OEM transmission cooler


Removing the front bumper/grill on my Odyssey was a must! Installation was pretty much straight forward once you confirm the feed, and return connection points. Mounting the actual cooler to the front radiator was the easiest part of the job. My Odyssey made two 650 mile trips pulling 2050 lbs with no problems so I’m very happy with the cooler!


Great product, I’m currently in the middle of the installation.


good product form a great company !
only complaint is this was listed as for my specific truck, but the "insta-dapt" supplied doesn't fit the Dodge truck of my year. even doing my research ahead of time, it seems to be hit or miss whether it would fit as some of them come with 5/16 fittings and some (like mine) come with 9/16 fittings. it doesnt matter the engine size, even other 3.7L dodge trucks of the same year have 5/16 fittings... I think Dodge made a change middle year, but never let the consumer know as mine is a late year '04.
no dig deal as I was able to assemble it anyways and got it up and running great and both the radiator and trans are running much cooler now !
I attached the D12902 to the bumper as you will see in attached images.
2 attached images are just before finishing, bumper hasnt been attached yet, one of them is after everything was complete.


Works solidly, much better than the optional stock tranny cooler. It doesn't get temps as low as another one I've had, but it doesn't leak like that one either! Always keeps temps within acceptable range, though at the higher end of acceptable when pulling 7-8k in 110*F outside temps and hills. Be prepared to fabricate a mount for it, not a one size fits all kit!


This fan looks like it will do a great job.
more overheated transmission.
Pulling a trailer in stop and go traffic on a 100 degree day - No problem :-)

Show More Reviews

See what our Experts say about this Derale Transmission Coolers

  • Best Transmission Cooler for a 2018 Chevy Silverado 4.3L V6
    Since your 2018 Chevy Silverado has the smallest engine of that model year, I recommend the Derale Dyno-Cool Tube-Fin Transmission Cooler Kit item # D12903. This is our largest transmission cooler for the 4.3L V6 engine with dimensions of 15-1/4" wide x 7-1/2" tall x 3/4" deep. This cooler will do a great job of keeping your transmission from getting hot when pulling a trailer with your Silverado or just daily driving. The Derale Cooler is made of lightweight aluminum. I have linked a picture...
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  • Comparing Plate-Fin and Tube-Fin Transmission Coolers for a 2019 Ford F-150
    Out of the Derale # D13503 and # D12903 I recommend going with the former over the latter on your 2019 Ford F-150. Reason being that the part D13503 is a plate-fin cooler which is more efficient than the D12903 which is a tube-fin cooler. I have attached some helpful articles to help you determine where the best location is to mount the cooler on your F-150.
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  • Available Class III Transmission Coolers for 2018 Ford F-150 with 2.7L V6 EcoBoost Engine
    We offer transmission coolers for your 2018 Ford F-150 with 2.7L V6 EcoBoost engine at several different price points. All are displayed on the linked page. The Derale transmission cooler # D13503 is rated as a Class III cooler. They also offer a slightly smaller and less costly Class III model, part # D13502 and also the larger Class III model # D12903. A slightly less-efficient Class II cooler is offered, part # D12906. For best overall value and performance I recommend transmission...
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  • How to Determine the Transmission Cooler Return Lin on a 1999 For F-150
    The easiest way to determine the return line on your 1999 Ford F-150 transmission is to start the truck, shift into drive but do not go anywhere. After about 15 seconds or so put the truck back in park and apply the emergency brake. Turn off the truck. Out of the 2 hoses attached to the transmission, one should be warmer than the other. The one that is cooler is the return line. It may sound a little too easy but it works.
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  • Parts Needed to Flat Tow 1999 Honda CR-V
    A transmission cooler like Derale # D12903 is intended for a vehicle that is doing the work of towing a trailer rather than for a vehicle that is being flat towed. Your 1999 Honda CR-V can be flat towed with all wheels on the ground whether it is has a 5-speed manual transmission or an automatic transmission. The flat towing preparation procedure is slightly different for each type of transmission but in both cases you'll want to ensure the transmission fluid level is full and that you...
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  • Recommended Transmission Cooler for 2016 Chevy Silverado 1500
    Transmissions should operate at right around 200 degrees ideally. The 215 degrees is a little concerning as 220 is recognized to reduce power and the life of the transmission, so I do recommend adding a transmission cooler to your truck. I recommend the Derale Dyno-Cool Tube-Fin Transmission Cooler Kit - Class III - Economy # D12903 to assist in cooling your transmission to keep your truck functioning well.
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  • Transmission Cooler for 2015 Chevrolet Suburban
    The largest transmission cooler you can fit in front of your AC condenser will give you the most cooling efficiency so I suggest Derale Cooler kit # D12903 along with Hose Fitting kit # D13035 for the 5.3L V8 engine. This cooler measures 15-1/4 wide x 7-1/2 tall x 3/4-inch deep; you will want to check the space in front of your condenser to ensure there is enough room to mount the Derale. The inlets/outlets can point in any direction. You will want to ensure that you can access the transmission...
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  • Best Solution for Lowering Vehicle Temperatures When Towing
    The added stress from trailer towing usually shows up as an increased transmission temperature. I am not sure if the gauge you're referring to is displaying engine coolant temperature or if you have one that shows transmission temperature. We do offer Derale Class III transmission cooler # D12903 for your 5.3L Yukon XL which measures a generous 15-1/4 x 7-1/2. This can be mounted in front of your AC condenser to provide supplemental transmission cooling after the OEM cooler in the radiator...
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  • Do Push Rods of Derale Transmission Cooler Kit # D12903 Damage AC Condenser Fins
    Using the push rods of the Derale Dyno-Cool Tube-Fin Transmission Cooler Kit # D12903 will not cause any damage to the condenser of your vehicle. The fins are designed to be slightly bent and not be permanently damaged. Also, no amount of damage to the fins would cause a leak as they only attach to the outsides of the piping of the condensor. If the fins get damaged all they do is prevent the condenser from being able to cool as efficiently.
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  • Transmission Cooler Recommendation for a 2007 Chevy Suburban Towing a 5,900 Pound Travel Trailer
    Adding weight distribution will help to divide the gross trailer weight more equally to all the axles of the Suburban and trailer, but all the weight will still be there. While weight distribution is a good idea for a trailer this size, the best solution, and most economical, is to add a transmission cooler. I recommend the Derale Dyno-Cool Tube-Fin Transmission Cooler Kit, # D12903. It is rated for up to 6,000 pounds gross trailer weight and will help to keep the transmission fluid in...
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  • Transmission Cooler for a 2008 Ford F-150 4.2 Liter Towing 5,000 Pound 5th Wheel Trailer
    The most popular cooler for towing capacities of around 5,000 pounds is # D13504. This cooler is 11 inches wide, 12 inches tall, and 7/8 inches deep. Provided you have space for a cooler, and on a 2008 Ford F-150 you surely do, this cooler will work great for you. I have linked a video review of the cooler, the instructions, and a help article on coolers.
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  • How To Find the Transmission Cooler Return Line From Radiator on a 1993 Chevy C2500
    The best way to determine which line on a transmission cooler is the return line from the radiator is to use the following procedure: 1. Start engine while engine is cold 2. Place transmission shift lever in drive for no more than 10 seconds 3. Place in Park, stop engine, and remove keys 4. Identify the oil return line by feeling both oil lines. The coolest line is the oil return line. On the aftermarket transmission cooler the ports are not input specific or output specific. It is not...
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  • Transmission Cooler Recommendation for 2014 GMC Yukon XL with 6.2 L Engine
    The great thing about transmission coolers is that they're fairly universal in terms of vehicle fitments- the biggest concern is finding the largest cooler that will fit in the forward most available mounting position with your 2014 GMC Yukon XL. The largest cooler we have available for your Yukon XL Denali is the Derale Tube Fin Cooler # D12903 which is 15-1/4" long x 7-3/4" tall-which is the correct size to mount in front of the air conditioner condenser fan (the most preferable spot)...
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  • Do I Need to Identify Transmission Cooler lines to Run an Aftermarket Cooler In-Line with Factory
    You will need to determine the flow of the transmission fluid in order to install the aftermarket cooler in-line with the factory. The fluid needs to travel from the transmission, to the factory cooler, to the aftermarket cooler, then back to the transmission. One of the fittings on your transmission should be marked RETURN. Trace this line back to the factory cooler. Disconnect this line from the factory cooler, and reconnect it to which ever end of the aftermarket cooler you choose...
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  • Does Transmission Cooler Install for 2004 Ford F-150 Require Hose Fittings
    You will want to use the hose fittings part # D13024 and # D13025 when installing the transmission cooler part # D12903 on your 2004 Ford F-150. They will make the process much easier and allow you to not have to cut and flare any hard lines.
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  • Transmission Cooler Options For 2014 Toyota Tundra SR5 4.6L
    We have class I # D13611, Class II # D12906, Class III # D12903 and Class IV # D12904 coolers for your 2014 Toyota Tundra SR5 with the 4.6L. I would suggest getting the Class IV just to get the most cooling for the purchase. They all install relatively the same so I've included an installation video to help you do it on your own!
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    For your 2002 Ford F-250 with 6.8L V10 engine the most popular transmission cooler option is the Derale Class III model # D13503 which installs with Radiator Adapter kit # D13025. This cooler measures 11 x 8-3/4 x 7/8-inches and it is best installed in front of your AC condenser where it will receive the most direct air flow. A video is included for you. The cooler can be installed with the two connection ports facing in any direction. Another option is to use a pan-style cooler. A pan...
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  • Towing Capacity and Transmission Cooler Installation on a 1999 Honda CR-V
    I was able to find on the Honda website the specs for your 1999 Honda CR-V. The towing capacity is listed as 1000-lbs. Transmission coolers come in a variety of types and sizes. These items are not vehicle-specific, so you can install the largest cooler for which you have space to mount it. The best location within the engine compartment is in front of the air conditioner condenser as this placement provides maximum air flow and hence best cooling. I have linked two articles that provide...
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  • Recommend Derale Aluminum Tube Fin Transmission Cooler For a Snowmobile
    We do have all aluminum coolers available, they are the 6000 series coolers from Derale. Checkout the Derale Dyno-Cool Tube-Fin, part # D12901, which is an all aluminum cooler. The # D12901 cooler measures 13 inches wide, 5 inches tall, and is 3/4 inches thick. You will need to measure to see if you will have room on your snowmobile to mount the cooler. We do not have an aluminum tube fin cooler as small as the Derale # D13212 cooler that you referenced. For other aluminum coolers in...
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  • Transmission Cooler For My 2010 Subaru Outback With Flat 6 Transmission
    We have a number of options for your 6-Cylinder, 2010 Subaru Outback Wagon, provided the transmission hose line diameter matches that of the transmission cooler. The Derale Dyno-Cool Tube-Fin Transmission Cooler Kit - Class III - Economy, part # D12903, has transmission hose lines that measure 3/4" in diameter. If the transmission lines on your Outback are the same dimensions, this cooler will work for your vehicle. You will have to measure the dimension of the hoses on your transmission....
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Info for this part was:

Employee DeAnne T
Updated by:
DeAnne T
Employee Daron K
Updated by:
Daron K
Employee Patrick B
Expert Research:
Patrick B
Employee Michael H
Expert Research:
Michael H
Employee Jameson C
Expert Research:
Jameson C
Employee Adam R
Expert Research:
Adam R
Employee Jacob T
Video Edited:
Jacob T
Employee Dustin K
Video by:
Dustin K
Employee Steven C
Installed by:
Steven C
Employee Bradley B
Test Fit:
Bradley B

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