These are the 1/2 inch thick cables that hold the rear corners of your cab down to the frame incase of a rollover accident, it keeps the cab from getting ripped off the frame. You're dead anyways if you're in a wreck that bad. Might as well enjoy it not squeeking

 

are you keeping your parts up front lubed up? my brother put a 6" on his 02 ext. cab and he had to keep the front end lubed up cause it had the 4x4 button instead of on the floor.