Tony: Noisy when accelerating usually means that there is heel contact on gears. The sound above 40 plus is heel/flank. I would suspect and check pinion bearings, may have lost preload or cracked cup. Should have even face contact with 6 to 8 thousandths backlash. Correct lube level should be around 6 pints. I think what has happened is that pinion bearings have overheated and are probably toast. Heat kills!! This will cause loss of preload, because of expansion rate of housing and spool is much greater amount than the pinion shaft, and ring gear. This will in effect unset the preload! As the housing grows from heat the rear pinion bearing will unload. Also the rear pinion bearing takes all the torque/thrust (accelerating/decellerating)forces, when overheated. Normally all pinion thrust is taken by the front bearing. Check with gear paint, but I'm sure thats whats happening from the sounds you described. You should also check gear hardness with a fine file as some annealing may have taken place on the pinion. The pinion gear itself is very prone to stress/distortion when it has been overheated. Check carefully, gear pattern and inspect pinion for any cracks on flank of teeth. You may very well just want to swap out the gearset and go with new bearings all the way around. Good Luck!!!
