I have an intermittent weird problem with my 07 4.0L Auto trans

Truck is sitting at about 43K miles.

At 30K miles I changed the trans fluid and filter. I used Amsoil ATF.
I did overfill it a bit and put a couple hundred miles on it before draining out the over fill. Did change (Aug 2010 might be '09 I can't remember) day before driving from S. NH to Carlisle PA for show. While at Carlisle I drained out the excess.

Weird problem first happened at about 41K miles and again at about 42.5K

What happened is after truck was started I started driving and it would not shift out of 3rd not letting me over 30ish MPH with high revs. Pulled over put in park let sit for about a minute and take off and problem is gone and truck shifts fine. Both times was after it rained out. First time was like 10 minutes after the Springfield MA Tornado (April 2011) while I was in Springfield. Second time was just after a regular rain fall(Aug or Sept 2011) at home.
It has rained and snowed since than and the truck has not had this problem. Tuck has also sat for a week at a time with still no problem.

Any thoughts.

Thanks.

 

i had a similar problem with mine it would also slip when taking off from a stop so i put in that lucas stop slip/leak transmission additive and it went away