Sounds like low/bad fluid or the pump is dying. Could be wrong pully on the pump turning it too slow/fast maybe?
Did this just start? When does it make these sounds?
I run 32's with 2 1/2 lift and stock pump with stock cooler and it's nice and quiet. I replaced a leaking pump when I bought my 74 back 16 years ago (from NAPA, life time W) and replaced it last winter (yeah I had the recipt so free). My Bronco see's mostly street use so stock pump works well.
Tim