I was waiting for my truck to warm up in the a.m. before work, while sitting in the truck, in park, i felt a strong jerk, kind of similar to releasing the parking brake with your foot off the brake.

Funny thing is, a few years back, I noticed a neighbors truck do the same thing after they got home from work. They parked, went inside, their truck jerked forward causing their alarm to go off.

I should add, this is a 2005 SCREW 4x4 xlt with 83,000 miles on it