Having issues with my daughters 05 Cherokee 3.7 with NAG1 transmission. A few months ago it started banging out of 3rd gear and going into neutral under heavy acceleration. I swapped the valve body with a used one from the junk yard. Fixed the problem for about 3 months. Now it's doing it again but banging out of overdrive and going into neutral. I replaced the TC lock up solenoid and the conductor plate. It's still having the same issue. I can shift it to neutral and back into drive and it acts normal until it pops out again. Tonight my daughter explained to me that it might be slipping through 1st and possibly 2nd gear. Any have any experience with the NAG1's? Any help would be appreciated

 

I believe the '05 is a Cherokee (KJ) - you may not find much help in this forum as it is for the (KL) series...

 

OP is likely asking about a GRAND Cherokee in which case the https://www.cherokeeforum.com/f5/ forum would be more appropriate.

Or if outside the US, it could be a Liberty (which was marketed as a Cherokee) and one of the Liberty forums would be a better place for info.