I have a 2000 Big Bear 400 4X4 I bought new in 2001. It is in great shape,adult ridden and always garaged.
I didn't notice it until a hunting buddy pointed it out but my Big Bear's rear end is really sitting low. It seems to ride fine and I never noticed anything but judging from tire clearance it is low.
I assume the rear spring is probably shot? Anything else to check? Thanks!

 

If you have never needed the extra ground clearance, why bother? Many rear shocks are adjustable for stiffness, from the parts drawing, yours is, but if the adjuster will move after rusting quietly for 19 years is another matter.