99 Yukon 4l60e 1-2 2-3 Shift Lurching only when cold

[brycebba]

My wife told me yesterday as she left the house that when her car would shift from 1-2 or 2-3 it lurch and gave the description that it felt like a manual car being shifted a bit too low in rpm and lugging it where it does that kind of jerking motion. Unfortunately I haven't been able to get it to happen and it only happens when the engine and transmission are cold and once it's gone about a mile or two tops it stops and everything shifts great..

I checked the fluid both hot and cold and its within normal range, it's a good color, and smells normal. I read through the entire 4l60e sticky and I couldn't find anything that seemed to match these symptoms. Any suggestions on what to look for or what it could be?

 

[brycebba]

Bump. I have done more research and still have no clue what to test or fix

 

[brycebba]

It was raining non stop for a week here in Utah and when it stopped and dried out on Monday the problem hasn't happened since I guess. Could be a coincidence but I wonder if there is some connection that was getting wet or something. Any ideas? I don't my wife and little boys getting stranded somewhere.