2010 4.0 SOHC, automatic, 4x4 etc... When it is rainy or damp the truck is intermittently hard shifting into second and third. SOMETIMES Bangs in hard sometimes it doesn't. Chasing this problem I replaced so far the cam position sensor, mass air flow sensor, checked, tightened and lubricated the grounds with dielectric grease I also checked the three plugs on the computer which the centre one had water in it. I cleaned the plug out with electronic contact cleaner and covered it in dielectric grease. This seemed to temporarily resolve the issue but now it is back. The computer plugs are still dry. I checked. So where else could this problem be coming from? Could it be the Transmission pressure solenoid? Maybe the plug is corroded? Any other ideas? I been trying to figure this out for over a year and had to to a few garages to no avail. one had me replace the battery *eyeroll* anyway. ANY help will be appreciated.

 

Had this happen last week while it was raining what should do is put few sand bags in the bed due to fact they are light trucks.
When shifting in rain in any gear how many rpm are you running at ?

 

I would do what you did before, check connections.
Di-electric grease doesn't conduct electricity, which is why it is used on electrical connectors.
Since it doesn't conduct electricity it is VERY important that this grease doesn't get on any connections, metal to metal contacts that need to pass voltage or ground, if it does then they can get intermittent.

Most OBD2 readers can get transmission codes but not all, if solenoid or shaft speed sensors were intermittent then computer(PCM) will set a code for that, it won't turn on the CEL(check engine light), just puts the code in Memory because it isn't a full time problem.

Check TPS(throttle position sensor) connector, 3 wire, clean and dry

One other thing, do you notice any fluctuation in the speedometer needle, is it steady, no small wavers.