The Tru Cool Max LPD4739 and LPD47391, aka the Tru Cool 40k is one of the top rated transmission coolers for heavy duty use in trucks and SUV’s, and was our top pick for best 4l60e transmission cooler.
The Tru Cool 40k gets its name from having a GVW (gross vehicle weight) rating of 40,000.
| Transmission Cooler | GVWR | Type Of Cooler | Price |
 Tru Cool Max LPD47391 | 40,000 | Plate & Fin | Shop Now |
 Tru Cool Max LPD4739(Includes thermal bypass) | 40,000 | Plate & Fin | Shop Now |
Tru Cool 40k With Thermal Bypass
While both are very similar, there are two different part numbers, the Tru Cool 40k:
- LPD47391 – No thermal bypass
- LPD4739 – Includes thermal bypass
The thermal bypass allows for transmission fluid to heat up quicker and restricts flow through the cooler body until it does.
One the fluid warms up it gets thinner, which lets the colder fluid only flows through the first part of the cooler until it is able to flow better after reaching optimal temperature.
If you live in a colder climate, the Tru Cool 40k cooler with thermal bypass is best.
It is recommended to utilize the stock transmission cooler in the radiator with the Tru Cool Max LPD4739 to allow the fluid to get to operating temps.
Tru Cool 40k Specifications
The Tru Cool 40k trans cooler features a highly durable double brazen aluminum construction with precise fin spacing to ensure efficient airflow through the body for maximum cooling. With its 13 rows of cooling, the cooler does a phenomenal job at keeping temperatures in check.
It uses 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.
Size:
8 1/2″ x 22″ x 1 1/4″
Type of Transmission Cooler:
Plate & Fin
Number of Cooling Rows:
13
Gross Vehicle Weight (GVW):
40,000 pounds
Fitting Size & Type:
The Tru Cool 40k fitting size is 3/8″ inverted flare hex with 5/8″ thread size
Installation Kit:
Includes universal installation kit with rubber transmission line, fittings, clamps, and mounting hardware
Recommended Uses
- Full size Trucks & SUV’s
- Performance vehicles
Since the Tru Cool 40k is such a popular transmission cooler upgrade on GM full size trucks and SUV, there are a number of specific brackets designed to make installation as simple as possible on these trucks.
Tru Cool 40k Transmission Cooler Installation
Installing the Tru Cool Max 40k on most GM trucks and SUVs is simple due to the large amount of space behind the front grille, which is the best place to install a transmission cooler. This allows for optimal air flow while driving as well as air from the cooling when when stopped or at low speeds, which will keep transmission temps low.
Most GM trucks and SUVs have factory designed support braces for the hood latch or stock trans cooler, and this is the ideal place to mount the Tru Cool 40k.
The below video demonstrates how to install the Tru Cool 40k on a 4l60e equipped Chevy Tahoe.
What We Like About the Tru Cool 40k Transmission Cooler
- GVW Rating of 40,000
- Includes cold weather bypass – Perfect for towing in colder climates
- Fitting type – The inverted flex flare provides a more secure connection to the transmission cooler lines assuming the right fittings are used
- Can bypass the stock cooler – This cooler is large enough to use as a stand alone transmission cooler
- Includes universal installation kit for simple installs. Kit comes with transmission line, fittings, clamps, mounting hardware
Conclusion
Overall, the Tru Cool Max it certainly one of the preferred transmission coolers for 4l60e equipped trucks and SUV’s that need superior ATF fluid cooling. Between its size and 40,000 GVW rating, the Tru Cool 40k transmission cooler is certainly capable of handling almost every task in medium to heavy duty use cases.
Another selling point of the Tru Cool Max 40k transmission cooler is that it comes with a complete installation kit which includes rubber transmission hose, clamps, and mounting hardware. Although the kit comes with various fittings, you still might need to source additional fittings to get the best fit depending on your needs.