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Transmission Coolers > 1999 > GMC > Sierra

Derale Transmission Coolers for the 1999 GMC Sierra

Derale Transmission Coolers

ratingratingratingratingrating (1 reviews)

Code:   D12903



Shipping Special

Shipping Weight: 3 pounds


Derale Dyno-Cool Tube-Fin Transmission Cooler Kit - Class III - Economy - 1999 GMC Sierra

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 GMC Sierra'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 GMC Sierras 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

Customer Reviews

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

Average Customer Rating:  ratingratingratingratingrating4.0 out of 5 stars   (1 Customer Reviews)

- D12903

ratingratingratingratingrating by: Jeff F06/29/2011

Is this review helpful?

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. 18179


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.

comment by: Robb B. - 10/22/2013


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.

Patrick B - 10/23/2013

Ask the Experts about this Derale Transmission Coolers
Expert Answers about Derale Dyno-Cool Tube-Fin Transmission Cooler Kit - Class III - Economy - D12903                                            Do you have a question about this Transmission Coolers?

  • 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 to be
    view full answer...

  • 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
    view full answer...

  • 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.
    view full answer...

  • 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 much
    view full answer...

GMC Sierra Accessories

Info for this part was:

Photos by:
Theodore B

Updated by:
DeAnne T

Expert Research:
Patrick B

Expert Research:
Michael H

Expert Research:
Adam R

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