I know this is an old post but maybe it will help someone else out if they come across this.
I changed my struts a couple days ago and I had the exact same problem. I had no idea what the rubber was. But after messing around, I believe that is the top part of the Shock Absorber Boot that just broke off. You can remove it and the new boot fits right into it.
Question about Nissan Pathfinder Part #54036
in 96-2004 R50 Pathfinders
Posted
I know this is an old post but maybe it will help someone else out if they come across this.
I changed my struts a couple days ago and I had the exact same problem. I had no idea what the rubber was. But after messing around, I believe that is the top part of the Shock Absorber Boot that just broke off. You can remove it and the new boot fits right into it.
NissanPartsDeal.com
54057-0W000