Transmission slipping/banging under load

[Basspro46]

2015 ram1500 slipping/banging when it downshifts while pulling boat up long hills. Acts and drives normal at all other times while pulling boat, transmission serviced approximately 1 year ago at 100,000 miles

 

[Wild one]

2015 ram1500 slipping/banging when it downshifts while pulling boat up long hills. Acts and drives normal at all other times while pulling boat, transmission serviced approximately 1 year ago at 100,000 miles

If a dealer serviced it,the first thing i'd check is the fluid level.
You need the rear tires roughly 9" in the air to level the transmission.
Follow these instructions to a T,don't try and cheat and miss a step or 2.
The ideal checking temp is between 100F and 105F,so start with a cold transmission.The 122F temp is the max checking temp,not the ideal checking temp.
This is assuming you have the 8 speed,if you have the 6 speed,disregard these instructions

 

[Burla]

step one have to check fluid level, sad to say they make it harder then it needs to me.

 

[Hemi395]

Making sure the pan is level is CRITICAL for getting the proper fluid fill. I don't see how that's possible to safely do on a lift...