I suppose, the act of violently smashing and releasing the E brake a couple times is going to inevitably rock the truck a little. That might be what the whole issue is. The springs aren’t strong enough to work on their own without a little give from the rocking? I was wondering why so many posts talk about rocking the vehicle to release the e break. But there may actually be something to it. But man, if you’re sitting on an incline, what can you really do?
The best way to move a vehicle is by literally putting hands on the tire and rolling it versus trying to push the deadweight of the entire vehicle from the hood or trunk. You go straight to the source. If you have another person around you could smash and release the pedal while it’s Rocking. On an incline, you may have to stand on the tire with a foot a little down each side to be able to rock back-and-forth.