i have a 02 rubicon with 1800 miles and i ride 99% in hi D1, sometimes in esp, low for mud and step hills, but D2 seems to escape me really not sure what it is. the manual says it is for carrying heavy loads or towing(torque). i never really tried it for that but going down a smooth flat trail i put it in hi D2 and it seems more like a overdrive of somekind. i can get it up to like 20mph and hardly touch the throttle and it i can keep it there. it like keeps the speed up but the revs down.

 

acording to my manual its for when you want maximum traction were you dont want to spin the wheels.
like on slippery roads or ice.
thats what the book says.
its like a soft toch.
you dont want to use it for towing heavy loads or anything like that.
its just a smoother shift pattern.
it dosent rev as mush befor it shifts to the next gear.
and if you were to tow with it in d2 the tranny would be working harder then in d1 and would probly get over heat and burn the clutches in the tranny.

 

I use D2 for trveling lon stretches of trail. It drops the rpm down so I figure it is easier on everything. One time riding a nice trail from Big Springs, ID into West Yellowstone and back, 64 miles round trip using D2, we got 28 mpg with 2 riders and lots of cargo. Don't use it a lot, but still use it.

 

Clutchs in a rubicon?? From what i read it doesnt have clutchs its hydostatic,kinda like the zero turn mowers.I could be wrong, but i remember when i took mine back to the dealer for its first service they said didn't have to adjust the clutch cause it has none.

As far as D2 i agree it seems like it shifts quicker and is really good for smooth trails,short highway trips etc.You can get the same results by using ESP if you upshift sooner then usual.As far as towing i only tow heavy loads in low ESP to keep the tranny from trying to shift when its under a load.
In low theres no diff between D1 or D2 there the same.