1badI-5

I have a 3.5L Colorado with a 4L60E and I was getting on the highway so I gave it some gas and then it dropped down into gear then felt like it went into neutral. I let go of the gas and then the gear kicked in I have never had any problems with the transmission. I have a tune and a super servo. now the truck wont shift out of gears until I get into 3k rpms and shifts hard no slipping. Anyone ever experienced this? my check engine light isn't on.

Thanks,