Treacle JK/JKU Heavy-Duty Ball Joints are engineered to handle the increased load caused by oversized tires and offset wheels. FITS: JK Wrangler (2-door) w/ Dana 30 or 44 axle JKU Wrangler Unlimited (4-door) w/ Dana 30 or 44 axleINCLUDES: Upper ball joints w/out knurl - pair Lower ball joints w/out knurl - pairUPPER BALL JOINT FEATURES Extremely hard sintered wear bushings to handle extreme side load demands w/out failure Magnesium Phosphate coating to inhibit corrosion throughout Heat treated 4140 chromo ball/stud & 1045 carbon steel housing Factory-style serrated flange nut & grease fittingLOWER BALL JOINT FEATURES Hard alloy tool steel slotted wear plate for ball/stud to socket wear protection Wear plate features grease channels for increased flow through entire joint ensuring longevity & predictable operation Magnesium Phosphate coating to inhibit corrosion & friction throughout Heat treated 4140 chromo ball/stud Huge 30mm (1. 18”) ball Factory style serrated flanged castle nut Ball joint pre-load adjustability provides the end user w/ near effortless wear adjustment (kit includes Preload Adjustment Tool) Low-profile single lip dust seal eliminates torn conventional dust boot concerns Adjustable ball stud retaining ring for accurate initial & future preload adjustments that can be done w/out any axle disassembly Adjustable preload can be performed w/ simple hand tools Adjustable end cap w/ two zero fittings allow greasing access from either side w/out axle shaft removal even w/ larger RCV shafts Dual helical grease grooves machined in the retaining ring allow spent grease to exit through the low-profile seal Low-profile seal prevents contaminants, while allowing spent grease to evacuate from the ball joint