First thing to check is the pinion nut and make sure it is tight and that there is no slop in the bearings. The pinion will try to pull back into the case on decelleration altering the setting If all is well the gears are set to shallow.

I 've run up to 5:13's in 8-3/4's with no noise issues. If The gears are set up wrong they are possibly already torched. They wear a pattern very quickly. After running them, Re-setting them may quiet them down but there will most likley be some noise left

Tim