my 98 sohc has auto tranny and when in drive if i let of the gas it starts to grind and when i put it in reverse it doesnt engage it just grinds please help me out need some things to check i have checked the fluid and it is to the right level and is red not brown now what????

my 91 does something like that, but it is the clutch packs in the trans that are shot, because mine "grindes" like that when it tries to shift out of first, so i no longer drive it untill i can find a trans for it.