2007 outlander rear suspension squeak

This has always done it since I have had the machine, but finally wanted to look into it. When I push the rear end of my atv side to side I get a loud squeaking sound and a lessor squeak getting on to ride. But if I put straight up and down force to compress the suspension and let it come back up no squeak at all. Ideas? the sound is comig from the suspension/swing arm area for sure.