When I pass at wide open throttle on the highway I'm noticing that sometimes it'll neutral out (high RPMs with no power). I'll let off it, and it'll grab. It doesn't do this if I give it some acceleration and just drop down to 3rd gear but if I floor it and it jumps down to 2nd, it'll neutral out. This is the only weirdness I'm having with my trans (98 Vulcan). Any ideas what could cause this?