By now everyone should know that excessive heat is the leading killer of automatic transmissions. Hard working diesel trucks are no exception to this rule. Simply doing what diesels do best, which includes towing heavy loads, pushing around big off-road tires, or racing sports cars light-to-light, can quickly push trans temps into the red. Add in more power from a performance tuner, or transmission tuning that increases line pressure, and you can really cook a transmission quick.
Installing an aftermarket cooler is a great way to combat high fluid temperature. However, most of the time this requires custom fabrication and difficult installation of a universal, on-size-fits-some, heat exchanger. Fortunately for ’01 to ’10 Duramax owners PPE has a bolt-on solution that’s as functional as it is simple.
| PPE’s ’01 to ’05 transmission cooler replacement features 60-percent more surface area than the factory cooler, which leads to a 20 to 30 degree drop in fluid temperature. All necessary brackets and hardware are included, and the install takes less than an hour. Newer ’06 to ’10 trucks us a different cooler, but never fear PPE has those covered as well.
| The install starts by removing the truck’s grille and the cover on top of the radiator. How this is done is different depending on year and make (Chevy or GMC) but the basic idea is the same. After removing the one bolt (if your grille has it) gently pull to release the clips securing it to the core support. Once removed you’ll have access to the factory cooler.
| Before the factory cooler can be removed the fluid lines need to be released. Start by using a small screwdriver or pick to remove the plastic cover over the fitting clips.
| Next, using the same tool, gently release the clips that secure the lines to the cooler. Be careful, as these clips are under tension and have a knack for flying across the shop.
| Knowing which cooler is needed is as simple as looking at the color of the clips, in theory anyway. Over time the color fades. Looking closely you can see that the clips from our ’02 Silverado are orange, indicating that these fittings are in fact from an ’01 or ’02 and haven’t been changed. Clips found on ’03-’05 trucks are purple.
| Now it’s time to remove the factory cooler. If you’re truck has an exterior temperature sensor start by removing the plastic clip holding it to the factory bracket.
| Then the two plastic clips on the cooler bracket can be removed, followed by the four bolts.
| You’ll need to save the two slide clip nuts from the factory cooler as they will be reused on the new bracket. Be careful when removing these clips, as they can become brittle over time and have the tendency to break.
| We’re at the halfway point now, with the factory cooler and brackets removed and ready to install the new PPE unit.
| With the factory junk out of the way it’s time to install the new cooler. First the lower brackets need to be installed on the PPE cooler and the new upper bracket installed on the core support.
| The bolts should be left loose so that the final adjustment can be made when on the truck.
| When installing the new cooler first align the fluid lines with the fittings on the bottom of the cooler. Next, position the cooler so that two top bolts can be started, followed by the lower bracket bolts.
| Lastly, tighten all of the bolts, reinstall the fluid line clips and covers, and attach the air temperature sensor (if you removed one). Start the engine and check for leaks before reinstalling the grille and basking in a job well done.
Tips & Tricks
• Install the cooler lines in the new cooler before working on the top bolts (lock clips are still installed last).
• Lubricate the inside of the fittings and cooler lines to aid in fitting.
• If the locking clip doesn’t fit like factory then the cooler line isn’t fully seated.
• Some grilles have a small (10mm) bolt near the hood latch, some don’t.
• ’03 and newer Chevy grilles will snap out with a long screwdriver.
• Care needs to be taken with GMC grilles as they can break easily near the headlights.
• Use a simple twisting motion when reinstalling the lock rings (and don’t forget the black retainer).
• Have a catch can ready as the cooler and lines will leak fluid when removed.