When you drop the suspension on the passenger side the axle will sometimes contact the subframe and keep it from dropping enough. Loosen the two subframe bolts on the passenger side all the way and put them back in 2 full turns. This will allow the suspension to drop down further so you can remove the strut assembly. Remember to tighten them back up afterwards! You cant believe how many times people call with knocking noises and they forget to tighten the subframe back up.