This link states 6823124AI is for 2014 - 2017:

2014-2017 Ram Outside Rear-View Mirror, Left 68231241AI | Mopar eStore

2014-2017 Ram Outside Rear-View Mirror, Left 68231241AI

store.mopar.com

and 68462827AA is for 2017 - 2022:

2017-2022 Ram Door Mirror 68462827AA | Mopar eStore

2017-2022 Ram Door Mirror 68462827AA

store.mopar.com

However, to verify the exact replacement Mopar part numbers for the mirrors it is best to check using your truck's VIN, as depending on model and options, there are multiple versions of the mirrors.

I went through this recently. I was provided a Mopar part number for my year and model (not by the dealership), but when I went to the dealership parts department they used my VIN and identified a different part number as being the exact replacement for my truck. When it came it it was the exact matching mirror unit.

 

I had the same issue and the same question about replacing the motor and gears. No can do. You will need to buy and install a new mirror unit. I went through the dealer to make sure I got the right unit.

 

Yes you can replace the motor/gears. These guys make the parts: GruvenParts.com | Custom Upgraded Car and Truck Parts |

I replaced both of mine about a year ago, and no issues. Great parts.
Takes a bit of work and a lot of patients, but a bunch cheaper than replacement units that have the same cheap motor/gears.

 

I'm guessing since alot of people are saying that they've had this problem before,I guess these are notorious for failing.I also had got this problem and still have this problem unfortunately its only for the driver side mirror and the motor has gone out.I have a Lonestar as well same mirrors but with chrome.i cant for some reason find the motor.

 

I ordered the gear/motor kits, since fixing stuff is what I do, but you can buy the complete unit, still requires disassembly of the mirror, but that is the easy part.
2013-2018 Ram Power Folding Mirror Gears and Motors - Gruven Parts

post if you have any questions.

 

I ordered my replacement motor and gear sets from GruvenParts, and finally had time to replace them today.

The how to video on the site is a great video, a little long winded in some ways, but definitely got me through it. I found a much easier way to remove the glass than what was shown in video.
Detache the upper part of the glass as shown, but to disconnect the lower glass mount, tilt the mirror adjustment back upward and tilt the top of the glass toward you. Then lightly pull outward to unseat the glass as the lower retainers are just hooks that have just enough grip to not let it just fall off once the upper clips release.

First side took a little longer, mainly tryin to open the assembly to get the motor and gears out, but the second one was much easier. Beats the heck out of buying completely new assemblies.

I would highly suggest if you are doing one side, go ahead and do both.