Hi: I'm looking at a TT that weighs 6,876 lbs with a hitch weight of 890 lbs = 7,766 I want to get a Dodge Ram 1500 with a 5.7L Hemi V8. The 3.55 axle has a max towing of 8,550 and the 3.92 axle tows 10,050. I'm assuming I'll be better off with the 3.92. What's the difference in the axles that allows the 3.92 to tow more weight? Thanks so much for your help.