These ball joints employ a metal on metal design to improve durability and performance.
;California Residents: WARNING Synergy Manufacturing D30/D44 Heavy Duty Ball Joint Set (Upper & Lower) - 4120-04 Replace your Jeep's factory ball joints with Synergy MFG's NEW Dana 30/44 Heavy Duty Ball Joint Set. Get rid of that steering wander and play caused by loose or worn out ball joints. A must for vehicles with lifts and larger tires.Set has one upper and one lower ball joint, two sets required per vehicle;New and improved ball joints;Compatible with all aftermarket axle shafts (including RCV) with no modifications needed;Fully greasable metal on metal design for prolonged life;Ball joint bearing surface area is considerably larger than stock due to elimination of the inner nylon liner for a longer lasting joint;Ball joint housing is manufactured from sintered graphite, bronze, and 1045 steel for a strong, smooth, bearing surface;Ball joint stud is manufactured from induction heat treated 4140 steel for maximum strength and smooth operation;Ball joint dust boot is made from wear/tear resistant black nitro-butile rubber (NBR);12 month unlimited-warranty (see warranty information);Synergy high performance grease (4119) recommended;Notes: Metal on metal ball joints require a small break-in period of typically 100-500 miles to fully seat the bearing surfaces.