What causes clumping noise in rear when putting in gear.

Hi, you did not mention if you have a front wheel drive equipped Equinox or an all wheel drive version. If it's all wheel drive, it's possible you could have driveshaft noise - such as from a worn universal joint. There could also be a concern inside the differential in the rear, or a concern with suspension components in the rear as well, due to shifts of vehicle torque and weight from drivetrain engagement. Hands on inspection is important to determine where the noise originates from. https://repairpal.com/auto-repair-near-me Click the link or call us at 877-913-1554. We'll gladly find you a certified RepairPal shop in your area.