2016 SV V6 Differential maintenance

Hi folks,

I just bought a 2016 SV king cab a week or two ago, and want to do all the maintenance I can myself. From my research this truck seems to be relatively easy to work on, and at least for the first several maintenance intervals there's nothing complicated that would involve more than basic knowledge and tools I either already own or can get easily. I am a fairly handy person, I've done all the maintenance on my home myself (including emergency maintenance and routine maintenance) and have done oil changes and similar work on my cars in the past. This is just the first time I've owned a vehicle and a house from the start, where I can do all the work myself. Previously I've been in apartments.

I am not a beginner to basic car maintenance, but I am a beginner when it comes to owning a truck and doing all the maintenance myself beyond oil changes and other things everyone should know how to do like changing out bulbs and things like that.

I bought the truck used with 3800 miles, and the dealer's already done the 5k service since they got it in on trade with 3600 miles. I will likely change the oil anyway at 5k or close to it. I do have ramps which I've used to change oil in the past but likely won't need them for the truck since there's a good bit of ground clearance, and ramps are useless for tire rotations anyway.

I have a question regarding the differential. I will likely have more questions as time goes along, and I'm not ashamed to say something is out of my league and hire a mechanic. But so far, most everything I've researched seems pretty simple and there are good videos on YouTube for nearly everything I need to do.

I have an SV V6 with automatic transmission 4x2. Obviously I don't have a transfer case, but looking in the maintenance manual at 10k I need to inspect differential oil and change it at 20k if towing (towing is planned in the future, perhaps not before 20k but definitely at some point during the life of the vehicle). How can I inspect this fluid without changing it? There is no dip stick, and the maintenance manual does not specify that I see.

Outside of that, if any of you have tips regarding maintenance please feel free to share! Thanks a lot!