I have a 2014 grand cherokee limited awd. Im at 99600 Miles and just developed a "shudder" (one tech even described it as like a "fish-bite on a hook" feeling) when going 2nd to 3rd and 4th to 5th gear. I had bad engine mounts and that didnt fix it.
IT ONLY HAPPENS WHEN THE CAR IS WARMED UP.

I am maybe thinking torque converter?
Service techs in two places are saying its a "non-servicable transmission".
Thoughts?

 

You'll have more chance of a responce in the Grand Cherokee section here: https://www.cherokeeforum.com/f5/

 

While I don't have much experience with newer model stuff, I can definitely try to help. The 2014+ Grand Cherokees all have 8 speed transmissions. It sounds like this is an issue during acceleration since you're saying it happens 2nd-5th gears. The classic "fish bite" under acceleration is 90% of the time caused by secondary ignition. At 99,600 miles, I'd check a couple of your spark plugs for wear. Most newer cars have gone to long life 100k mile plugs. My experience is that they sometimes don't make it that far. Especially with higher compression or forced induction engines. Good luck!