Fabtech 15-18 GM C/K1500 SUV 2WD/4WD 4in Budget UCA SystemFabtechs replacement DOM upper tubular control arms feature heavy duty extended range ball joints that provide additional strength to the front suspension. The new ball joints provide unrestricted movement throughout the suspension travel range for smooth operation. On 4WD models the front differential housing is relocated to retain proper CV angles at the new ride height, while a 1 4" thick steel skid plate protects the front diff.