Had a similar problem, could not get trans. into lower gear after driving through some drifts. Took a screw driver slid underneath and started chipping. Just be careful when you start getting close to the shift cable and the NSBU switch. That or find a heated shop and let it thaw out for 24 hours.
2002 2500 D/A LT 4x4 CC LB LT - Edge Juice, Ispro boost/pyro guages, 265/85R16, High Idle, OD lockout, Swiss Cheeze Air Box, Timbren Rubber Ride, Extra Leaf Spring<br />2004.5 3500 D/A DRW LT 4x4 CC LB - Edge Juice w/Additude, 235/85R16, High Idle, Swiss Cheeze Air Box, Timbren Rubber Ride