Look for the VIN sticker, it will have your GVWR.
It should be 6800 lb for the V8, 6500 for the V6. Figure the vehicle weighs in at ~5000 lbs and subtract that from the GVWR printed on the VIN sticker and that's your effective payload capacity if you aren't towing.
The stock tires on the Overland have a load rating of 107 which equates to 2149 lbs per tire x 4 = 8596. None of the 18" tires on Tirerack have a lower rating, in fact most are 109 or higher. Now, that doesn't mean you can load it down to 8596 lbs, just that your tires could handle it so the tires aren't the culprit.
To figure out how they calculated the number you are seeing involves some math. It's confusing but not that complex.
First, you always work from the highest number or the Gross Combined Weight Rating (GCWR) which is different than the GVWR as it includes any trailer you might have connected. From the owners manual, page 449 you get the following numbers:
3.6L 4X2 8900 lbs Trailer = 5000 lbs
3.6L 4X4 8900 lbs Trailer = 5000 lbs
5.7L 4X2 13100 lbs Trailer = 7400 lbs
5.7L 4X4 13100 lbs Trailer = 7200 lbs
Now, you work backwards by subtracting the trailer weight.
3.6L 4X2 8900 lbs Trailer = 5000 lbs (8900 - 5000 = 3900)
3.6L 4X4 8900 lbs Trailer = 5000 lbs (8900 - 5000 = 3900)
5.7L 4X2 13100 lbs Trailer = 7400 lbs (13100 - 7400 = 5700)
5.7L 4X4 13100 lbs Trailer = 7200 lbs (13100 - 7200 = 5900)
Now, looking at these numbers it becomes immediately obvious that there's no way you can ever tow the max trailer rating in a V6. Honestly, based on the literature I would have expected the numbers to me more like:
3.6L 4X2 11500 lbs Trailer = 5000 lbs (6500 + 5000)
3.6L 4X4 11500 lbs Trailer = 4810 lbs (4x4 is 190 lbs heavier)
5.7L 4X2 13460 lbs Trailer = 7400 lbs (6800 + 7400)
5.7L 4X4 13460 lbs Trailer = 7150 lbs (4x4 is 250 lbs heavier)
That leads me to believe the significant reduction in GCWR on the V6 is due to the transmission, not the suspension or frame. It also leads me to believe they used averages since the base Laredo is lighter then either the Limited or Overland, mostly due to the pano roof. Anyway, back to the calculations on the V8.
So, still working backwards we have 5900 lbs available after we hook up the largest trailer. Subtract the base vehicle weight and you get the max payload capacity.
5900 - 4850 = 1050 lbs
Now you know how they arrived at the number on the placard. So, if you aren't towing the actual payload capacity of the vehicle is the GVWR minus the base curb weight.
6800 - 4850 = 1950 lbs.
Oh, one more thing to remember. If you are towing you must add the tongue weight to the payload to ensure you don't overload the vehicle. In theory that would mean the payload available after you loaded the trailer would only be 330 lbs (1050 - 720). In practice you rarely load to the max trailer weight so a drop in 1000 lbs will actually give you back the tongue weight plus 280 payload.
The math lesson is done for the day but there will be a test later