About 2 months ago I had some transmission work done. The connector, harness, etc were corroded from moisture getting inside.

Last week when it first started to get cold (also after a wet weekend) I noticed it won't shift into OD the first attempt. At least not easily, I haven't tried to really go past 70 in this condition. But my rpms will hit almost 3 getting to only 65mph... then normally when I let off the gas and try again or just eventually it will shift and my rpms will keep around 2 no matter what. Seems to be worse in the morning.

It seems to shift fine any other time besides when getting on the freeway and trying OD (or last gear).

Could this be because of newer parts? The torque converter? The cold mornings? Please someone tell me I don't have to go back to the tranny mechanic!

Thank you in advance for any help

2008 Explorer Eddie Bauer
V6
4.0
5 speed (I think it's a 5 speed, my manual says it could be a 5 or 6)