clothes washer shredding clothes

i've recently had my washer (top-loading Sears
Kenmore/Whirpool, i think ~1999) suddenly
start ripping clothes up, i mean literally shredding them.
It's happened so far
to two thick towels & a pair of pajama bottoms... they
look like you put them
thru a strip-cut shredder & you see some holes in them,
like they got caught on
something & then yanked.

i got something flat & stuck in underneath the agitator to
see if it would catch on
anything, but no luck... so how do i remove the agitator
to see what the problem
is? i can't seem to pull it out. Or should i just call
Sears tomorrow? This has been
a reliable washer up to now, never a problem.