My M5OD with Castrol ATF+4 would crunch going into 2nd and 3rd if shifted fast, plus a low whine driving in 4th. As recommended by a couple of posts at Bob Is The Oil Guy, drained & filled with one quart Redline MTL and the balance with Mobil1 ATF. 2nd gear shift is perfect now; 1 - 2 shifts and 3 - 2 shifts are very fast, no grinding at all. 3rd gear shift is better but not perfect; it doesn't grind but it still has a bit of a hitch if shifting fast. 4th gear bearing whine is a bit better but still there.

This is in 90F weather. I'm hoping that cold weather shifting will be OK with that single quart of MTL.