The concept of paddle shifters is pretty straightforward. When you hit the plus paddle, the transmission shifts up, and the minus paddle makes it downshift. This is the case for most cars with paddle shifters and traditional automatic transmissions. However, when the GMC Sierra is equipped with paddle shifters, those paddles do something a little different.
The paddle shifters on the steering wheel of a GMC Sierra operate a feature called Electronic Range Select (ERS). Drivers can enter manual mode by pulling back on the shift lever to “L” (Low). When the L in the shift pattern lights up red, ERS is engaged. From there, the left steering wheel paddle reduces the highest gear available, and the right paddle increases it. For example, if the dash says “4L,” that means gears 1-4 are available, and it won’t shift higher than that.
GM recommends using this mode while driving downhill or towing a trailer to limit the truck’s top gear and speed. Electronic Range Select is intended for truck purposes rather than for performance or driving engagement, like most vehicles with paddle shifters.
Notably, this only applies to GMC Sierra models with a console-mounted electronic shifter. Sierra HD models with a mechanical column shifter have what’s called Range Selection Mode, which effectively does the same thing as Electronic Range Select. In lieu of paddle shifters, there are plus and minus buttons on the column shifter. When the truck is shifted to L, the plus/minus buttons select the desired gear range.
GMC Sierra 1500 AT4 in L9
Speaking of the paddle shifters, they can do a little-known trick that V8-powered GMC Sierra drivers might be interested to know. When you shift the truck to L9 using Electronic Range Select, the Engine Control Module (ECM) disables Dynamic Fuel Management (DFM), the truck’s cylinder deactivation system. It also deactivates the auto start/stop system, ensuring all eight cylinders are firing the whole time the truck is running.
Comments
Transmission shop owners recommended to me, unless you drive a diesel with an exhaust brake, use your vehicle’s regular brakes to slow down on a downhill grade. They are far easier and less expensive to replace than your Tranny’s clutch packs.
SOMETHING ELSE THATS NOT NEEDED
I’ve got a 2020 HD2500 GMC, with a 6L90E trans. My column shifter has that option, but I’ve never used it, as I don’t see a practical use for it, unless I’m towing in a mountainous area and engine breaking is required. As it is the towing mode already holds gears too long, but it does provide engine breaking to an extent.