when i'm driving down the road and i hit about 35 my tc goes into lock up and make a grinding kinda noise. it locks up tight because i can blip the throttle and the rpm stay and don't rise like when not in lockup. it only does it in lock up and under throttle if i let off the gas it goes away or if its very light throttle it goes away but if i go say up a slight incline it will make the noise. its a draging grinding gggrrrrrr but not deep, like medium pitch i guess. is this normal?? tc is yank 3000