The 2014 Chevrolet Silverado And GMC Sierra

Thursday was the most important day in General Motors Co.'s recent history.

The company rolled out its all-new Chevrolet Silverado and GMC Sierra fullsize pickups.

For the past two decades, these two trucks have long been the bread and butter for the Detroit-based carmaker, outselling nearly everything else combined. But the Silverado and Sierra have followed a tougher road this year.

While Ford Motor Co. and Chrysler Group's Ram 1500 continue to draw rave reviews and have seen a spike in sales, GM sales have remained tepid.

Through November, Silverado sales are up .1 percent and Sierra sales are up 4.4 percent, while Ford's F-Series sales are up 11.7 percent and Ram pickup sales are up 20.3 percent.

GM has also said that it has an oversupply problem with its current pickups and will have to carefully monitor those inventories as it prepares to roll out these all new pickups in the late spring next year.

No one is underestimating the importance of these two new trucks, which are part of GM's new six truck strategy – which includes Chevrolet and GMC heavy duty pickups, as well as small pickups that will be shown next year.

Already, Chevrolet and GMC are touting all of the new features on these pickups, which include three new engines, loads of technologies and smart features like LED lighting in the bed and a bumper step that makes climbing into either truck easy.

Click through to check out some of the coolest features that debuted on the Silverado and Sierra.

The new Silverado will come with three different engine choices -- a 4.3-liter V6, a 5.3-liter V8 and a 6.2-liter V8. 

All three engines, known as the EcoTech3, will feature direct injection, variable valve timing and active cylinder shut-off.

While final power and fuel economy numbers were not released Thursday, the expectation is to see more power as well as higher fuel economy in all three gas engines.

The cylinder deactivation will shut off four cylinders in the V8 engines and two cylinders in the V6 engine when power is not needed and the pickup is cruising.

The all-new GMC Sierra will arrive with the same EcoTec3, which will be built in Tonawanada, N.Y.

The new exterior of the Sierra includes a new front end and changes around the body, including inlaid doors, which help provide a quieter ride.

All around the body, designers have added additional details and attempted to give the Sierra a professional look.

The GMC Sierra will feature projector beam headlights with LED trim above and below the head lamp.

The use of LEDs will help give the Sierra a distinctive look during the day and during the night.

The Chevrolet Silverado receives a similar treatment to its front end with a new dual port grille and stacked headlamps.

The LTZ model will come with projector beam headlamps as well.

The entire body has been stylized and the Silverado will come with wheels to match, measuring in size between 17  and 20 inches.

The beds in both the Silverado and Sierra feature an easy to open and close tailgate.

The tailgate uses a internal torsion bar that winds up as the gate is lowered. This makes it possible to lower or lift the gate with two fingers. Furthmore, the tailgate no longer slams down, instead, it gently lowers itself.

GM has added optional LED lights under the bed rails as well, which will make it easier to see things in the bed. There are also tie down bolts in all four corners.

Beds will come in three sizes: 5-foot-8; 6-foot-6; or 8-feet.

GM will also offer a bumper step on the Sierra and Silverado. This step, on each end of the rear bumper, called CornerStep, allows a person to stick their foot in the bumper and step gently into the vehicle.

Both the Silverado and Sierra will feature significantly upgraded telematic systems. Chevy will continue its MyLink system, while GMC will offer its next generation IntelliLink.

Both systems offer the ability to use apps from your phone and play them on the stereo's large touch screen.

There will also be Bluetooth connectivity for hands free phone operation.

The redesigned center stack along the dash has been nicely laid out and is easy to use, even if wearing work gloves.

For both the Silverado and the Sierra, the interiors have been overhauled.

Many touch points have been softened and materials upgraded. The Crew Cab models will offer more space than ever before. (Crew Cab models can also come with a larger 6-foot-6 bed.)

Furthermore, GM will introduce heated cloth seats (with material that is more difficult to stain) and a number of other upgrades.