I have a 2002 3/4 ton 4x4 Duramax 130000 miles. When engaged the four wheel drive is poping (like a broke tooth on the gerar). It initionally started at twenty mph, now it does it at any speed. At twenty it was bam. Bam. Bam not seeming to be a broken tooth due to speed and rotaion of gears. Pops about the same at low speed as well. Could the actuator not be fully engaging? Next problem is away from four wheel drive. After coming to a medium to hard stop the truck feels like the rear end is going to fall out of the truck when releasing the brake. Changed u-joints and new brakes all the way around. Even backed off the e-brake cable just to see if it was binding to no avail. You guys are great. Thanks for any suggestions.