My wife drives our 03, 1/2 ton Suburban as her daily driver. I drove it last week and noticed right away that it has a shift problem. When it shifts from 2nd to 3 rd it free wheels for a few second and revs to about 3500 before it engages. If you take your foot off the gas at the sift point, it will drop into gear and your good to go. It seems to only be with the 2 nd to 3 rd shifting. I asked a few people and they all asked about reverse. No problem with any other gears.
Is it time for a trans job or is it the selinoids or something else?
Did you check the fluid level?
If level is good, maybe a fluid and filter change would help.