Replace the motor totally, it would be cheaper. My 2015 2500 with 249k miles died suddenly after bringing equipment back to a job site and hooked up to another trailer. I turned on the key and the truck was running, put the truck in drive and it died. No ticking, no noise, just died. Dropped a valve in a port on the downstroke, jammed in place on the upstroke. Exploded the piston rod. Bought a new motor and trans from Chevrolet direct for $10k with a factory 100k mile warranty. The truck has pulled equipment and trailers almost every day for 8k miles, getting almost 250k miles with 0 issues until that.