The MPC trucks(wheels) are all the same. They aren't defective, just poorly designed/executed. Some are worse than others depending on when & where they were made - the same basic wheels are still used on the starter set RS-3 diesels with the truck mounted DC motors.
You could replace the wheels with sintered powdered iron wheels from a postwar 200/600 series truck with or without the traction tire slots, or replace the whole power truck with a 600 series MagneTraction truck(the GE 44 ton trucks are a near identical cosmetic match).
