2014 TL SH-AWD. --- PSA
I had been having some issues with my revs fluctuating at 1400 to 1900 rpm when accelerating in 4th or 5th gear @ around 30mph. Sometimes it would jump +- 50 rpm, sometimes +- 400 rpm.
It felt like it was my transmission hunting for the correct gear. Like it wasn't sure if it needed to downshift to get up a hill etc..

I decided to do an oil, air filter, and transmission fluid change as shown in this video:
So far (only driven twice), I'm not getting the rev fluctuation. We'll see how that holds up in the next few weeks.
I assume the transmission fluid change was the fix, as last time I did an oil change (~4500 miles ago) the issue persisted.

Bonus picture of my car's ass.

 

Nice ass

 

if you had transmission slipping issues, try the 3x fluid change and change the trans filter on the 3rd time. Since you've already did one change, change it again, then drive it for 15 min, drain, fill again and change the filter. My friend had similar issues with his TL and everything went away after doing the 3x drain and fill. Shifted like butter afterwards. It was a ton of work changing it then driving 3 times in a row, but that helped get most of the old dirty fluid out.

 

Love the rear and wheels. That blacked out emblem and white paint is just beautiful!