Our 2014 GMC Sierra has been through quite the makeover throughout the past few months. We began by bolting on a ProCharger for extra eco-friendly horses, moved on to installing a JBA exhaust and headers, dropped her down thanks to a MaxTrac lowering kit, and replaced our OEM brakes with Hawk Performance brake kits for that extra stopping power. We’ve reached the final stage of our track-devouring daily hauler build. With the help of Torco, our 6L80 and 5.3L is protected with fresh fluids, along with a trans cooler we installed from Derale. We’ll measure any changes in performance via data logging.
And so we got to work on the build’s final stages, starting with the transmission. After draining the trans and removing the pan, we could replace the stock filter and gasket. From there, we could bolt the transmission pan back on at 80-inch lbs.
To ensure efficient transmission cooling, we opted to install a trans cooler from Derale Performance. However, this wasn’t just a plug-and-play experience. First, we had to remove our Sierra’s front grill, exposing our ProCharger’s intercooler. Being quite large, the fan needed a new place to mount. Using a piece of sheet aluminum, we cut and drilled it to the perfect size to accommodate the cooler’s bracket for that perfect fit. Once behind the intercooler, we used nut-serts on the cooler bracket to fasten things up!
The most challenging part of these builds is ensuring everything connects and fits as required. More often than not, as we saw with our cooler fan, things aren’t usually entirely compatible. Some modifications or fabrication may be necessary for the aftermarket parts to work with the OEM components. Thankfully, this wasn’t the case with the connection of our cooler. An adapter is needed to connect to the factory lines, and the cooler conveniently included an AN to NPT adapter in the box, making our lives just a little bit easier. Another solution could’ve been completely removing the factory lines on our Sierra and replacing them with AN lines from the cooler to the trans. That would not only create more unnecessary work but another adapter would then be needed on the tranny itself. We think we made the right decision using the included adapter, and everything works as expected!
Final step; getting the fans all wired up. Here we were met with several options:
- Wire directly to the cooling fans for instant and continuous use.
- Wire to ignition on so the fans will run as soon as the car is turned on.
- Wire to a temp switch, which will only run the fans when the temperature exceeds a certain number and automatically turn off when things get cooler again.
- Lastly, wire the fans to a manual switch, giving the driver complete control of the fans where they see fit.
We went with the last option. We just felt it was the right choice for our needs. Now, we can control exactly when to power the fans, even turning them on before some spirited driving to ensure things stay cool. Remember, prevention is better than cure! Another advantage of being in control is the prevention of the tranny getting too cold. You’ll want to ensure your fans are off during those cold winter drives. The trans fluids will need to come up to temp, and the transmission and coolant temps can be vastly different. This may incorrectly hinder our decision regarding when to run the fans in certain circumstances. Thus, we may do a temp switch later.
Once the fluid change and trans cooler installation were complete, we fired up the data logger and drove the truck to see what we gained. Transmission temps were running 26 degrees cooler than before. That’s enough drop in running temps to make us believe in high-quality fluids and the Derale cooler. On the drag strip, we were somewhat limited by cold temps but managed a best 1/8th-mile pass of 9.24 seconds at 77.9 mph. This is a tenth of a second better than the last session after installing the ProCharger, and almost a full second quicker than the baseline 10.06-second pass when the truck was factory-stock.
This project has been fun, and we are happy with the results of turning a stock daily driver into the ultimate do-all truck. If you’ve got something similar in mind for your truck, here are some final thoughts on the build from the truck’s owner, Scott Parker.
Final Thoughts On Our Project GMC Sierra From Scott Parker
Our ProCharged 2014 GMC Sierra has been a faithful companion for the last five years, daily driving and towing Project Payback through the hills of SoCal. It’s even been to LS Fest West and Muscle Cars at the Strip. And it has performed near flawlessly in all arenas.
It’s certainly got some miles on all the parts, and throughout the project, I don’t have a lot I’d change. The MaxTrac lowering kit maintained the ride quality, pretty close to stock. However, it’s not so low that you have to worry about scraping every time you leave a parking lot or go over a speed bump. Occasionally you may clip a curb with the plastic air dam (under the front bumper), but that’s about it. The Yokohama tires proved a better overall tire than the OEM rubber, but really shined in the rain (yes, it does actually rain in SoCal.)
The ProCharger kit delivered on its promise of power you can really feel. To say nothing of the enjoyment from stoplight to stoplight, which was painfully boring when stock, it really did make it a much better truck for towing – even on sketchy mountain roads through San Diego County. The fit and finish were also near OEM quality, and it never affected the truck’s reliability.
The JBA exhaust and Hawk brakes were welcome upgrades I would do again in a heartbeat. The truck sounds muscular but still civil and stops well for something so heavy. And they both fit perfectly. The oil cooler, as mentioned above, also fits well and does its job.
If there is anything I would do differently on the entire project, it would be to go from the manual switch to a temperature-controlled switch on the oil cooler fan. It’s a minor change, and I may still do it. I would also be tempted to freshen the trans and try tuning it, but that may also be the one-step-too-far that ruins a great combo (something I have certainly been guilty of in the past on projects). From my understanding, since the trans controls don’t affect emissions, this may be legal or at least allowed in California.
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