grinding noise

My washer is making a grinding noise only during the wash cycle during agitation. The agitator dogs catch when turning by hand. Spin cycle is good, spins the clothes dry and the noise only happens during agitation. Video of noise attached for reference. What could be causing this noise?

Looking to help my girlfriend from buyind a new pump. After changing her filters (for high minerals causing rusty water) her pump started making a grinding sound while running, more from the impeller area than the motor itself. I'm thinking that possible bits of rust may have become freed and...