This is my second set of GM OEM replacement front shocks for a GMC Yukon Denali with Z55 Autoride. The original set lasted 130,000 miles, the first replacement set of AC Delco # 580-434 lasted about 50,000 miles before leaking and loosing gas-assist. These OEM shocks are very expensive at about $230 each. But they are the only OEM-type replacement that will keep your Autoride functioning normally. I hope the second replacement set lasts longer than 50,000 miles.