I have a 2019 F250 diesel , I just purchased a new 5th wheel RV, had bumper pulls before. When driving does it help to use 4 wheel drive high? Or do I just use the tow haul and pull knob out for positive traction? I have a 6.7 liter engine.

 

Short answer....NO! That 5th wheel will haul/tow lots easier than your bumper tow. No knobs pulled pushed, LOL! Tow mode is a good idea although I have a 20 F-250 with the 7.3 gas Godzilla towing 36' 5th wheel around 13,ooo lbs loaded. Weight police here will tell you you're overloaded...you're not! It tows like a dream, and you have more torque than I do. If I'm on the interstate basically level ground I don't use tow mode, I figure with the 10 speed transmission it will find a suitable gear!!!

 

Thank you that is pretty much what I thought but always ask when pulling something new. Appreciate your input.

 

We just completed a round trip from Wilmington NC to Mt. Rushmore. I have a 2017 F-250 Super Duty with the 6.7L Diesel. 5th wheel, 13,500 trailer, (2023 Grand Design 320MKS) and it towed like a dream. No issues at all other than fuel mileage was poor, 9 mpg when hooked up. I installed my hitch and a "in the bed" trailer connector.
Safe travels!

 

Actually that 9 mpg sounds more realistic than the 11-12 some here claim to get. Especially if the tow 70 or so..

 

Just drove 860 highway miles (1720 round trip) towing a 8,500 lb RV, one passenger and several hundred pound of gear in the bed. I averaged 11.5 MPG.

 

That’s a 7.3? I can believe that with 8500 lbs. my 5th wheel 50% heavier.

 

I apologize Obe, I shouldn't say :I can't believe that". May I ask average speed,? I'm sure thats possible but I bet you barely went over 60 MPH. I say that because I towed a 7500lb T.T. that was butt empty From Edgewater, FL to Myrtle Beach S.C. to trade in on a new 5th wheel 11,000 lbs butt empty. (Big mistake trading where I did in Myrtle Beach). Anyhow when I saw the height of the 5th wheel I was nervous about towing it. 3500 lbs heavier!! Hard to believe but I swear I got about 1 MPG BETTER mileage towing the 5th wheel with absolutely zero sway. Mu theory? The 5th wheel sits lots closer to the cab and the truck windshield acts like an air damn directing the air over the 5th wheel., as opposed to towing a wall 12' or more behind the cab. Even at that IF I keep speed 65-70 which is aggravating to me, the best I can hope for is 7.5 maybe 8 with no load MPG with no head wind. 2020 F-250 with the 7.3 Godzilla with 3.55 gears.

 

Don, I have the diesel like the OP. Speed averaged about 68mph. I also use a cetane booster.

 

The new 6.7 is quiet and powerful, but I still like the mileage I got with my 02 -7.3 ps 2wd always 11-12.5 mpg depending on terrain and head winds . Usually 68-70 mph. Did this while towing my 34’ft titanium 5th wheel 10000 lbs
I attribute some of this to its design and shape. The nose overhung the bed of truck all the way to the cab, with a sharp angle to the rear, this allowed the wind to come over windshield and right up to nose of rv and over
Too bad they don’t build the same 7.3 ps or the Titainium any more.

 

Oh O

Oh, o'k Obe. Again I apologize. I forgot you have the diesel. Yes I know they get a little better mileage. I've found with my 7.3 I try to have a qt bottle of Lucas Fuel treatment/Injector cleaner. I've used it for almost a yr and find if I add a couple ozs each fill up I consistently average around a MPG towing and 1-2 not towing better MPG. I'm sure I could skip a fill up now and then but at about $12 a qt it only costs a buck or less per fill up. The little single shot bottle I believe is around $5-$6 or so , the qt definetly is the way to go. I believe the reason it works is lousy gas??

 

A 5th wheel definitely is cheaper to tow and I agree with you on the reason!! Imagine the power and fuel mileage the newer 6.7 would get with no pollution crap like your 7.3!!