Kind of a notorious breakage on the 20's from what I hear. Worst part about replacing it, is getting it out so far in front of you and trying to hold it up and stoop down under the walkers as you start to slid it in. And mine was a 4420, so I'm thinking yours is bigger! Maybe someone has some cool tips about getting it in there, but I just man handled mine. Just check the shaker bushings and stuff like you noramally would, other than that good luck with your new part.