Best Transmission Cooler
for the Chevy Colorado

The Chevy Colorado is a midsize truck that people tow with well past what its size suggests — boats, side-by-sides, small campers, dump trailers. That is exactly the duty cycle that cooks an automatic: heavy load, modest engine, low road speed, not much airflow. A midsize truck's factory cooling has less margin than a full-size, so on a Colorado that works, an auxiliary transmission cooler is one of the smartest cheap upgrades you can make. It is a driveway job for most owners.

First, identify your transmission, because it sets your fittings and how you plumb the cooler.

Which Transmission Is In Your Colorado?

• 6L50 (6-speed): the early second-generation Colorado, roughly 2015 to 2016 with the 3.6 V6, ran the GM 6L50 six-speed. Smaller cousin of the 6L80. Adequate but heat-sensitive when towing near the truck's rating.
• 8L45 (8-speed): roughly 2017 and up V6 Colorados moved to the 8L45 eight-speed — the light-duty member of GM's 8L family. Good gearing for towing, but the 8-speeds want clean fluid and controlled temperature to avoid torque-converter shudder.
• 8L90 (8-speed, heavier): the higher-output and ZR2-oriented trucks pair with the beefier 8L90 in certain years. If your build is the performance or off-road variant, confirm which 8-speed you have before buying fittings.

Because GM shuffled engine and transmission combinations across model years and trims, verify yours by the RPO code on the glovebox sticker or by the gear count, then match your cooler fittings to the truck.

Stacked-Plate vs Tube-and-Fin — Buy the Right Kind

Stacked-plate (plate-and-fin)

Fluid weaves through rows of stamped aluminum plates with fins between them. Far more heat rejection per square inch than tube-and-fin because of the long turbulent path and big surface area. This is the correct choice for a Colorado that tows. It is compact enough to fit a midsize grille and still moves real heat. Derale and Tru-Cool make the good ones.

Tube-and-fin

Fluid runs straight through tubes with wrapped fins. Cheap and light, fine for a Colorado that only pulls a light trailer now and then. Under a real summer tow it will not hold temperature. Do not put one on a truck that works for a living.

Rule of thumb for a Colorado: tow anything meaningful, buy stacked-plate. Tube-and-fin is only for occasional light-trailer duty. Because the Colorado is midsize, fitment favors the more compact stacked-plate cores — measure your grille opening first.

Sizing for GVWR and Towing

A Colorado tows up to roughly 7,700 pounds with the right V6 tow package, which is a lot to ask of a midsize drivetrain. It is towing near that number where the fluid heats up fastest. Cooler makers rate their units by GVWR band; for a Colorado that regularly tows, pick a cooler rated a class above your truck's GVWR rather than right at it, because the rating assumes ideal airflow you will not get on a July grade in traffic. On a midsize truck, watch fitment while you upsize — you want the most capacity that still fits the grille opening cleanly. Aim to keep sump temperature under about 200 F cruising and under about 230 F under sustained load.

Mounting Location, Thermostatic Bypass, and Line Size

Mounting location

The aux cooler goes in the airflow ahead of the A/C condenser and radiator, low in the grille opening. Space is tighter on a Colorado than a full-size, so measure before you buy and pick a core that fits without crushing airflow to the condenser. Mount it with brackets or foam-cushioned ties and make sure it cannot vibrate against the condenser fins — a rattling cooler will destroy your A/C condenser.

Thermostatic bypass

Important in cold climates. Fluid needs to reach operating temperature to shift and lock up correctly; a cooler that runs it ice-cold on a winter morning causes hard shifts and poor converter lockup. A thermostatic bypass keeps fluid out of the cooler until it warms, then opens. If you add a large aux cooler and see real winters, buy a version with a bypass or add an inline one. Derale and Tru-Cool both offer them.

Line size and plumbing

Colorado cooler lines are commonly 3/8 inch — confirm on your truck and match the cooler, hose, and fittings to it. Plumb the aux cooler in series on the return leg, after the factory cooling, so the hottest fluid passes through it last. Use ATF-rated 3/8 hose and proper clamps, double-clamp each joint, route lines away from the exhaust, and secure them against chafing. Flush and leak-check before you tow on it.

Our Colorado Cooler Picks

Tru-Cool 4739 (Max) — The Tow Standard

If your Colorado tows near its rating, the Tru-Cool Max is the proven answer on GM trucks. Big effective surface area, plate-style efficiency, and a reputation for actually holding temperature under load. Confirm it fits your Colorado's grille opening — on the tighter midsize front end you may want to check clearance or step to a more compact core. Add an inline thermostatic bypass in a cold climate.

Check Tru-Cool 4739

Derale 13503 Stacked Plate — Best Fit for the Midsize Grille

Derale's compact stacked-plate cores are a strong match for the Colorado's tighter front end: high efficiency in a smaller footprint that fits without choking the condenser. Clean fittings and quality brackets. If the full-size Tru-Cool Max is too big for your grille opening, this is the cooler to reach for. Derale also offers fan-assisted versions for trucks that crawl or idle a lot on a trailer.

Check Derale 13503

Hayden 678 — Budget / Light Towing

For a Colorado that is mostly a daily and only occasionally tows something light, the Hayden tube-and-fin coolers are cheap, small, and easy to fit in the midsize front end. Do not expect them to hold temperature under a heavy summer tow — they are light-duty. As inexpensive insurance on a truck that rarely works, they are fine.

Check Hayden 678

Derale 15850 with Thermostat — Cold-Climate Towing

For a Colorado that tows where winters are real, a stacked-plate cooler with an integrated thermostatic bypass gives you summer capacity without the winter cold-shift penalty. The bypass holds fluid out of the cooler until it warms, then routes it through. Buy this if you tow in the cold or want it done properly in a four-season climate.

Check Derale 15850

FAQ

Does a Chevy Colorado need an auxiliary transmission cooler?

If you tow, yes. A midsize truck has less cooling margin than a full-size, and the Colorado tows up to around 7,700 pounds — a lot for its size. That load heats the fluid fast. If it never tows, factory cooling is adequate, but an aux cooler is cheap insurance.

Stacked-plate or tube-and-fin for a Colorado?

Stacked-plate if you tow anything meaningful. Tube-and-fin only for occasional light-trailer duty. The plate design moves far more heat, and the compact versions fit the Colorado's tighter grille well.

Will a full-size cooler fit a Colorado?

Sometimes, but the midsize front end is tighter, so measure your grille opening first. If a large core like the Tru-Cool Max is a squeeze, step to a compact stacked-plate cooler that fits without blocking the condenser.

Do I need a thermostatic bypass?

In a cold climate, yes. It stops the fluid from running ice-cold in winter, which causes hard shifts and poor lockup. Add one on a large aux cooler if you see real winters.

What line size does the Colorado use?

Commonly 3/8 inch — confirm on your truck and match your cooler, hose, and fittings to it. Use ATF-rated hose and double-clamp every connection.

Should the aux cooler go before or after the factory cooler?

In series on the return leg, after the factory cooling, so the hottest fluid hits the aux cooler last before returning to the transmission. Flush the lines and leak-check before you tow on it.