about every 5 thousand miles my pinion seems to get loose. To get rid of the slop i tighten the pinion nut about a quarter of a turn < which is probably a no no>. I am not real familiar with rear ends, but i assume that is changing my lash. heres my question, is my piniopn bearing wearing out, or is the crush sleeve <if they have one> just crushing more? I am getting ready to upgrade the rear end, but i dont want to spend the money on a 12 bolt. I would feel better, installing new gears and an auburn pro in this 7.5, if i knew of a way to keep the pinion shaft from loosening up. Any comments would be appreciated. I also use et streets and launch at 4500 at the track. would i be wasting my time with this 7.5?