Your tranny won't fail on your first trip unless you massively overload, it will most probably not fail on a few more trips. However, keep in mind that max tow rating, in your case 2000 lbs, includes driver only. If you had 3 extra people and their gear you need to subtract that weight from 2000 lbs limit. If you do the math, you are border lining the limit or you even slightly over. So if you keep stressing the tranny with all that weight and without additional cooling, it will just die one day....