clunking after water pump replacement
 

I have a 2019 cx 9 that i had the internal water pump replaced recently. Since that was done I have this clunking feeling towards the rear. It happens when I'm going up a small incline. What seems to be happening is that it tries to downshift as I accelerate. Though I never paid attention to when it shifted before, it seems to reach 6th gear before I hit 40mph. There are no other issues with the transmission and it works great in manual mode. The mechanic checked engine mount bolts and the mazda dealer couldn't find anything. I just have a feeling something wasn't hooked back up properly or something. It was perfectly fine before the pump replacement. Any suggestions?