How to park with all four wheels locked to prevent sliding on snow

Question

2010 Silverado 1500 Extended 4wd; Southern Ontario

I recently parked my truck on a slightly sloped asphalt driveway on 1 inch of slushy snow. The driveway had a 1ft drop over 20ft, sloped toward the road, and I backed the truck into the driveway (truck facing the road). After putting the truck in park, I could feel it slide a few inches down the driveway on the slush. That was an alarming experience that I would like to avoid.

I didn't apply the e-brake, although I know that's a good practice. But it's my limited understanding it wouldn't have helped because the e-brake locks the rear wheels; the rear wheels were already locked due to the truck being in Park.

Should I be parking in 4WD-high (and apply the e-brake) to lock the front wheels, too, and reduce slippage? Is that a common practice?

I know I can remove the snow from the driveway before parking if it's my own driveway. But this wasn't my driveway.

Answer 1

With the transmission in “Park” and the emergency/hand brake not on, only the input to the rear differential will be locked. Now if either one of the rear wheels looses grip on the ice, what you would see is that it would in fact start to turn in the opposite direction to what you would expect. It would be being driven by the gripping wheel on the other side which is now free to rotate as the vehicle moves forward.

This would be the same effect if you jacked both rear wheels off the ground while in “Park” and turned one of the wheels by hand. The other wheel is still able to rotate in the opposite direction. The wheels are not locked, only the differential input is locked.

You should have applied the emergency/hand brake. Braking then acts individually on both wheels. One wheel loosing grip would not affect the other wheels braking ability.

Selecting “Park” relies on both wheels having a good grip on the road surface to hold the car.

Answer 2

was the reason that the truck was sliding that the front wheels were turning or were they sliding on the slippery surface while the foot brake was engaged? If it slides with the foot brake applied, it will slide in 4WD, otherwise your suggestion is good.