Transmission has been acting up

Hey I've got a 01 Aztek with the 4t65e transmission and it's been acting up a bit lately. It's got 200,000km on it.

When it's cold out (-5C or colder) it only likes to shift 1st and 2nd gear. If I get going about 60km/h it will shift to 3rd and then to 4th around 80km/h. But if I stop and go again it's the same way, sticks to 1st & 2nd gear. When it does shift it's not a hard shift, it's a nice shift.

If it's roughly +2C I can get in and go and it shifts perfect through all the gears without warming it up. When it is cold out the car has to run fully warmed up and driven for at least 10 minutes to get it shifting perfect.

I changed the filter and fluid a month ago when the problem 1st happened. The fluid was still red and not burnt. There was a no major metal filings in the pan only the normal amount of clutch mud.

I work at a shop and have alldatapro. It says for this problem it can be:
-A faulty 2-3 shift solenoid valve assembly is stock ON
-Debris is found in the valve body or the spacer plate

I was thinking though that this may not be the problem since it only happens in the cold.