Extremely loud clunk when shifting into drive/reverse

[silver billet]

When I select the auto parking brake feature in settings, and place the gear selector in P(ark) the parking brake engages like it should, but I have to manualy disengage it. I thought it would auto disengage when shifting out of P(ark) to D(rive) or R(everse). Is mine working coreectly or incorrectly?

If you hop in your truck, start it, put seat belt on, foot on brake, switch out of park; the park brake should auto disengage. Note that seat belt is required for this.

 

[ericd]

UPDATE***

So I tested out the parking brake advice and it worked like a charm. Completely smooth and quiet transition from Park to Drive so I guess it is indeed the PAWL on the inclined driveway. I guess I'll just be using the E Brake from now on.
Thanks for all the help

 

[Scram1500]

If there is enough weight resting on the pawl it can actually get stuck and will not disengage until the weight is relieved