overdrive slippage

[greenet2]

hey,

i'm a newbie

maybe somebody could give me a tip here.  i bought a 97 K1500 a couple months ago, 80k miles, and it runs great except for a slip when going into overdrive.  All shifts are strong, except if i try to lightly accellerate after coasting on the expressway i get some slippage / rpm hops around 1500 rpms for a second while it tries to upshift.

I'm almost positive it has a shift kit on it based on normal shifting behavior.  

I've changed the rear-diff fluid, have to change the wires and a lazy O2 sensor this weekend that are setting off my idiot light.  Also i really don't know the last time he changed the tranny fluid and filter, i may do that as well.  Plus I just got it back from the shop - leaky intake gasket

 

Anybody had this happen?

 

Thanks.