Air control Valve? I think something more maybe
I just got my truck out of the shop, new head gaskets, new clutch fan, new belts, hoses. Ok. Now 2 days ago I was driving home, and I noticed when I went front 4th to N the rpms didnt change near as much as normal. While in idle waiting for the light to change my rpms are high and when I shift to first they drop to what they should be. Only when I'm in neutral do the rpms go up. I think it's the IACV but I noticed it's not as easy to shift now either, like I used to be able to pop out the gear without using the clutch and shift it into the higher gear without using the clutch at all. Now I have to push the clutch in to shift, and sometimes I have to push harder for the thing to shift into gear. Could these high rpms mean my tranny is about to shit? Or is this all the IACV issues?