4l80e acting funky

[Lookin4the1]

I've got a 6.0 with a 4l80e. I've put about 600 miles on it since the swap and it wants to shift at odd points or too soon into overdrive or 4th. it will also downshift itself out of no where. when i start out in OD. I've just been manual shifting and going through the gears and usually leaving it in 3rd unless i'm 60MPH. do i have a bad VSS sensor?

I'm trying to get it tuned next week, but theres no point if the trans is acting all crazy.