I just returned from a 350 mile trip towing my 27 ft travel trailer with my 06 screw 4x4. I tried towing in o/d but it rarely shifted into o/d and if it did shift it did not stay so I turned it off so it would not shift back and forth. I ran aorund 65 mph at 2500 rpm and got around 8 mpg. Is this normal? My Yukon XL can tow in o/d and runs around 2000 rpm and gets 10-12 mpg.

 

I tow with mine in OD & it rarely shifts down unless on a hill. I have 3.73s, what rear gear are you running? Your trailer is probably heavier than my race car & trailer though.

 

My dad's 04 shifts in and out of overdrive with the slightest hill when he pull his 7K lb camper, so he leaves it out of OD, and only puts it in when the roads are flat and he's going a pretty good speed.(doesn't want the engine driving at 2,500 rpm).
We both fine a difference when towing with OD off. It appears the shift points are a little different, and it seems to pull better. There are other people on here that have said the same thing.

Even with no OD, he gets about 10 mpg. Sometimes a little better with some use of OD(11mpgs), or just a little worst with no OD and a LOT of hills(9mpg).

 

I get between 6.5-9 depending on speeds and grades.

i tow in OD on the interstate, off in all other conditions.

 

Yeah thats about normal id say your yukon probably has a different gear ratio tranny and engine so it runs at 2000 rpms

 

I towed a 24 foot boat with my 04 5.4L with 3.73's. It pulled fine and sifted out of overdrive when I hit a hill. I got 9.5 miles per gallon.

 

Both have 3:73 gears and the camper weighs about 7600lbs. I could get it into o/d around 70mph but it was kinda swaying in the rear and not very comfortable even with an equilizer and sway bar. It was comfortable towing at 65 mph.