The GM full size trucks are great in terms of maintenance as well as being easily fixed, which is why many older trucks are still on the road today. Since this platform is widely known for having a large aftermarket and being easily modifiable, you have plenty of options when it comes to improving your truck’s stock components.
One area that is simple to upgrade is with transmission cooling. The Silverado and Sierra have a number of transmission cooler upgrade options. and installing a transmission cooler on your truck is very simple for the average DIY enthusiast in your driveway in only a few hours.
Whether you drive your truck daily to work, use it to tow haul from time to time, or need to drive your crew to job sites, it is always recommended to install a transmission cooler to prolong the life of your transmission and keep you on the road.
Looking for a GMC Sierra or Chevy Silverado transmission cooler upgrade to help lower transmission temperatures in your pickup truck? You have a number of options for getting the job done. Here are our choices for the best transmission coolers for Silverados and Sierras.
Note: Looking for transmission coolers for a Duramax Diesel GM truck? Check out our Duramax Transmission Cooler Guide.
|Transmission Cooler||Direct Fit?||Type Of Cooler||Price|
|Tru Cool Max LPD47391||No||Plate & Fin||Shop Now|
|Mishimoto MMTC-K2-14||Yes||Plate & Fin||Shop Now|
|B&M 70274||No||Stacked Plate||Shop Now|
Silverado & Sierra Factory Transmission Coolers
One of the common questions that owners ask is does my Silverado have a transmission cooler? Yes, all Sierras and Silverados do have a transmission cooler, and depending on the years, there can be an external cooler in addition to the factory cooler within the radiator.
Below is the factory cooler that comes standard on many older Silverados and Sierras.
As you can tell, the factory cooler is not that big. While it may do a good enough job at keeping temps within a safe range under daily driving conditions, it is not capable of handling more stress caused by hard driving, towing, or hauling.
One of the best parts about having an external cooler from the factory is that you are easily able to upgrade to a more effective cooler since the transmission lines are already run to the front of the truck for an external cooler.
If you are looking for a simple, oem replacement automatic transmission cooler for your Silverado or Sierra, here are is a GM factory replacement cooler for most models from 1999 and up that came factory with a similar cooler. Shop now.
Silverado & Sierra Transmission Temperature
The ideal transmission temperature for your Sierra or Silverado is typically in the 160 – 180 degree range. It is much easier to keep trans temps lower in older trucks due to their simple transmission cooler line setup.
For newer models with a 6L80 or 6L90 however (2014+), the transmission cooler lines utilize a built in thermostat that remains closed and does not flow to the cooler until the fluid reaches 190 degrees. To combat this, many late model Silverado and Sierra owners will modify the thermostat to bypass it which allows fluid to continually flow to the cooler like it should.
The transmission temperature fluid temperature chart shows that 175 degrees is the ideal temperature. For every 25 degree increase in temps, the shorter your transmission’s life becomes. As with all vehicles, cooler transmission temps are always preferred.
Sierra & Silverado Transmission Cooler Lines
As stated before, you can find an external cooler on man Silverado or Sierra full size trucks. This is helpful when installing an aftermarket transmission cooler because the transmission lines are already there. However, over time, it is common to find your Sierra or Silverado’s transmission lines leaking and they will need to be replaced.
It is common that you will find your transmission lines are leaking due to rusting out over time, especially if you live in an area that is more prone to causing your truck to rust. The most common area for this is typically the section of line that runs on the passenger side by the engine as shown below.
How To Remove & Replace Transmission Cooler Lines on Silverado or Sierra.
Replacing the trans cooler lines on your truck is not to hard of a task. The hardest part will be removing the lines from the transmission. These fittings are typically held in by clips that go into fittings, which can make things easier or harder depending on how you choose to remove the lines.
Typically it is easier to remove the clips that hold the metal lines in place rather than messing around with a wrench in a tight space.
How To Remove Transmission Lines From Radiator on Silverado or Sierra
To remove these lines first peel back the small plastic cover on the fitting and simply use a pick or small screw driver to pop the clips out. It is always best to have a couple of extra C clips around when removing old ones due to the fact they tend to pop off with force and fly elsewhere.
Silverado & Sierra Transmission Cooler Line Diagram & Routing
The design of the transmission cooler lines on most GM trucks is fairly straight forward. If your truck has setup without a transmission cooler from the factory, you’ll only have 2 transmission cooler lines going to and from the transmission to radiator, the send and return. If your truck does have a factory cooler, then the return line at the top of the radiator will then go to the front of the truck to the cooler, rather than straight back to the transmission.
This often confused people who aren’t familiar with how to install a transmission cooler, and they confuse the send and return lines.
Below is a basic Silverado and Sierra transmission cooler line diagram showing the standard hot (send) and cool (return) lines as the flow through a factory cooler setup.
So whether you have a 4.8, 5.3, or 6.0 LS powered truck , an older 5.7 small block, or a more modern truck with an LT motor, the transmission cooler flow is very similar.
Note: Newer trucks with the 6l80 transmission have their cooler lines coming from the driver side of the transmission, but the same idea applies.
How To Install A Transmission Cooler On A Chevy Silverado or GMC Sierra
When it comes to installing a transmission cooler on your Silverado or Sierra, the process is fairly straight forward. For instance, since there is so much room in front of the truck behind the grille, you already know where the transmission cooler will be placed generally.
Most GM trucks have braces that are behind the grille which make for fantastic mounting points, and we highly recommend using these support bars to place your cooler.
Once that’s all situated, the next piece involves running the new transmission cooler lines and installing them in the new cooler.
If your truck came factory with a trans cooler, you can easily use the stock lines with some modification.
To watch Silverado and Sierra transmission cooler installation videos, continue scrolling to specific transmission coolers for more guidance.
Transmission Coolers For Sierra & Silverado
When considering a GMC Sierra or Chevy Silverado transmission cooler upgrade, there are a number of factors to consider, such as:
- Transmission Cooler Size – How well will it fit?
- Gross Vehicle Weight Rating (GVWR) – Cooling capacity
- Type of Transmission Cooler
For a full size pickup truck is it typically best to get a larger cooler that has a large cooling surface with a higher GVWR, and either a stacked plate or plate and fin construction.
With all these things in mind, our choices for the best transmission coolers for a Chevy Silverado or GMC Sierra include:
- Tru Cool 40k
- Mishimoto MMTC-K2-14 ( For 2014 models and newer)
- B&M 70274
Each of these transmission coolers will do a phenomenal job at keeping your trans temps down, even under the most extreme situations.
Tru Cool 40k - Best Heavy Duty Transmission Cooler
As mentioned before on Transmission Cooler Guide, the Tru Cool 40k is one of the top rated heavy duty transmission coolers. This cooler is widely used on a number of trucks and SUV’s, and is very commonly installed on Silverados and Sierras making it a great upgrade over your stock cooler.
In fact, there is plenty of aftermarket support for the Tru Cool Max 40k in terms of installation kits which help to make for a very simple installation. Because of this, the Tru Cool 40k is the best transmission cooler upgrade for your 1500 or 2500hd (6.0 or 6.2 gas engine) Silverado or Sierra.
The image below shows the difference between the Tru Cool 40k and factory external cooler. While many GM trucks come factory with an external cooler, it is not big enough to provide the cooling needed for towing or hauling simply due to its size.
Tru Cool 40k Specs
The Tru Cool 40k utilizes a large plate and fin design that provides ample cooling for all strenuous driving situations. With 13 rows of cooling, the Tru Cool 40k does a phenomenal job at keeping temperatures in check.
This cooler uses a 3/8″ inverted hex flare fitting, which allows for the use of 6 or 8 an lines and fittings for a more secure fit and greater fluid capacity.
Because this cooler is so large and provides extremely efficient cooling capabilities, you can use this as a standalone trans cooler if you so choose.
Cooler Dimensions: 8 1/2″ x 22″ x 1 1/4″
GVW: 40,000 pounds
BTU Rating: 45,000
Fitting Size: 3/8″ inverted flare hex with 5/8″ thread size – This is great for those looking to install custom transmission lines
Installation Kit: Yes – Includes universal installation kit with rubber transmission line, various fittings, clamps, and mounting hardware
Tru Cool 40k Pros & Cons
- 40,000 GVW Rating
- Low Pressure Drop System
- Specific Kits Available
- Includes Universal Install Kit
- Requires Extra Pieces For Install
Tru Cool 40k Silverado & Sierra Installation
When it comes to installing this transmission cooler on your truck, there is not too much complexity. The hardest part about the installation (if you are using factory lines) is adding new fittings to the existing lines so that the factory lines can be used. If you are uncomfortable with that you can always add rubber hose and barb fittings to the cooler, which are included in the kit.
As mentioned before, there are a number of aftermarket installation kits for the Tru Cool 40k that are designed for these trucks, so mounting the cooler is simple. The video below shows how simple it is to install a Tru Cool 40k on your truck.
See What Other Silverado & Sierra Owners Have To Say About The Tru Cool 40k
Mishimoto MMTC-K2-14 - Best Transmission Cooler For 2014+ Silverado & Sierra
Mishimoto is arguably the industry leaders in providing direct fit transmission coolers for specific vehicles, and their Sierra and Silverado transmission cooler is no different.
The Mishimoto MMTC-K2-14 is designed as a 100% factory fit which makes for easy installation and our top pick for best 2014+ Silverado or Sierra 1500 transmission cooler. This cooler comes as a complete kit and is built to provide serious cooling for your transmission.
One of the common issues with transmission cooling on the 14+ Sierras and Silverados is the bypass valve within the factory transmission line. This valve is designed to prevent complete fluid flow until the trans temps reach 190F+. While this is on the higher side, these trucks are equipped with a 6l80e transmission that relies on Dexron 6 (Dex VI) for its transmission fluid.
When installing this cooler, it is common to modify the factory lines to remove the valve. Between the addition of the Mishimoto MMTC-K2-14 and the valve bypass, you can expect significant drops in transmission temperatures.
Mishimoto MMTC-K2 Specs
The Mishimoto MMTC-K2-14 is designed a 27 inch wide plate and fin construction that is more than capable to handle all that your 1500 truck can handle.
The cooler comes with a complete installation kit that is specifically designed for your truck. This alleviates any hassles in trying to get things to fit and running out to the store for extra parts. All lines, brackets, clamps and fittings are designed to work with your 14+ truck and make install a breeze.
Because of the overall size of this cooler, you will need to pick up an additional quart of Dex VI to compensate for the additional 0.65 quarts of fluid capacity and to replace any fluid that may have leaked out during installation from the factory transmission cooler lines.
Cooler Dimensions: 27″ x 6″ x 1.25″
Cooler Type: Plate & Fin
Fitting Size: 3/8″ barb
Number of Cooling Rows: 14
Additional Fluid Capacity: 0.65 Quarts
Fits The Following Application:
2015+ Cadillac Escalade 6.2L V8
2015+ Cadillac Escalade 6.2L V8
2014+ Chevrolet Silverado 1500 5.3L V8
2014+ Chevrolet Silverado 1500 6.2L V8
2015+ Chevrolet Suburban 5.3L V8
2015+ Chevrolet Tahoe 5.3L V8
2014+ GMC Sierra 1500 5.3L V8
2014+ GMC Sierra 1500 6.2L V8
2015+ GMC Yukon 5.3L V8
2015+ GMC Yukon 6.2L V8
2015+ GMC Yukon XL 5.3L V8
2015+ GMC Yukon XL 6.2L V8
Mishimoto MMTC-K2 Installation
The Mishimoto MMTC-K2-14 comes with a complete transmission cooler installation kit that includes the correct size line and hoses, clamps, and mounting pieces. This makes for one of the more seamless transmission coolers on a Silverado or Sierra.
While the cooler may cost more than others, the cost is certainly made up for the direct fitment that is extremely easy to mount and install yourself in your driveway with basic hand tools.
Mishimoto MMTC-K2-14 Pros & Cons
Mishimoto MMTC-K2-14 Reviews
B&M 70274 SuperCooler Transmission Cooler
The B&M 70274 has been mentioned in our best transmission coolers for towing and rightfully so. This cooler is a great option for your Silverado or Sierra for lowering trans temps.
Like all B&M SuperCoolers, the 70274 utilizes a stacked plate construction that is strong and durable. The cooler also features a low pressure drop system that allows for fluid to flow through only part of the cooler before getting to optimal operating temp.
B&M 70274 Specs
Cooler Dimensions: 11″ x 11″ x 1.5″
Cooler Type: Stacked Plate
Fitting Size: 1/2″ NPT
Number of Cooling Rows: 48
B&M 70274 Installation On Silverado & Sierra
When figuring out how to install a B&M 70274 transmission cooler into a Chevy Silverado or GMC Sierra, there are a two of important factors to consider, routing the transmission lines and mounting the cooler.
Since the B&M 70274 uses 1/2″ NPT fittings, you will need to get the appropriate fittings to run the lines of your choosing.
B&M 70274 Pros & Cons
B&M 70274 Reviews From Around The Web
The Chevy Silverado and GMC Sierra are two of the most popular trucks on the road. They are highly dependable, easy and cost effective to maintain, and have plenty of aftermarket support for upgrading and improving factory parts.
This is also true with improving the transmission cooling capabilities on your truck. Not only are there plenty of options for a transmission cooler upgrade, but it is very easy for the average weekend mechanic to install a transmission cooler on their truck.