I have been using this fluid for about 8 yrs and 160k miles in my 01 blazer. The first 15 it used valvoline with no extra modifier and the chatter was pretty bad. I then added the modifier with the valvoline and chatter went away. When 30k came around i put the M1 in there and have changed it every 50 k. Everything is perfect. I have been reading many other posts talking about diff whine, noise, chatter using the M1. Has anyone else had as good luck with it as i have? Or if you had bad luck, what vehicle. Im wondering if it is just not correct for certain vehicles but okay for GM's