hmm my rear drums squeak after it rains, but ive never had them lock up on me, idk if the Rear wheel ABS would actually help or not, but if it does i thought it was standard on all of these trucks????

 

no abs isnt standard thank god

 

If youve never did any brake work before there probablyout of adjustment. id take the drums off and check the shoe linings and readjust the rear brakes.brake shoes are pushed onby the wheelcylinder at the top, so when theres too muchgap between the shoe and drumthe top edge of the shoe tends to grab. its probablymore noticable in wetconditions due to thedecreased traction.id give adjusting the shoes a try. hope this helps.