Noise after Pro 5.0 Install

Well I finally received and installed my Pro 5.0 shifter. I was expecting the shifts to be a bit shorter but it is still 110% better than stock. I've noticed that if I am in first or second gear at very slow speed I hear tranny whine when I gentley touch and let go of the throttle. Just want to know if this normal and is caused by the shifter having no rubber bushing. Thanks