Hello-
We recently purchased a 34ft 5th wheel trailer. What gas mileage should we be getting while towing it & what should the brake option be set at? Weight of trailer is 9500 dry. We are obviously new to towing this large of a vehicle. Thank you for any information you can provide!

 

Welcome to FTE.

I assume your '08 SuperDuty will be a 6.4 PSD. Don't have much experience with that engine but what I do tells me you should be in the 9-11 mpg range depending on speed, terrain, load, driving style, etc... I would suggest you try the model specific forum for that truck. There is a lot of knowledge and information available there.

https://www.ford-trucks.com/forums/forum30/


Setting the brake controller will be specific to the trailer and testing is your best method. Find an empty stretch of level road and try varying the settings on the controller between stops, starting at zero and stepping up to 10, or until you lock the trailer brakes. Then find a setting that comfortably stops the rig in normal braking balancing the braking between the truck and trailer.

With some experience you will learn to adjust the settings for conditions. What works on a smooth flat dry road may not work as well in the rain, or on gravel.

 

Setting trailer brakes with a manual transmission is quite easy. On a nice flat stretch at about 35-40mph push in the clutch and manually activate the trailer brakes, you want them set to where you can juuust feel the trailer brakes grab.

The truck brakes will stop the truck plus it's in bed cargo, or a about a 5k# trailer, the trailer brakes should stop just the trailer plus a tad bit more for those emergency braking events, but still be driveable and not lock up at every stoplight. Any more brake and you are wearing the trailer brakes more than necessary with every activation. You dont really want to feel the trailer push you any when stopping, nor drag you back while stopping. Setting them up this way you can feel the effect of just the trailer's brakes. I always set mine up that way every time I hook up, and it's always worked very well for us.
YMMV

 

on my 08 6.4, I had a lifetime average of 11.5 mpg. Towing 15 to 16K 5th wheels and many other trailers. I put 86K on that truck and it towed well.

I used a banks 6 gun on it that kept the emissions system intact and it did great.

Others are right, 25-3o miles per hour and see how the gain stops the load. I'd start at 4 and go from there.

 

i had the 2009 f250 manual tranny and towed a fith wheel .
dpf cat delete cold air intake averaged 13mpg

 

We get 13 MPG towing our 2016 Sundance 267RL, but got 12.5 MPG towing our 2011 Montana High Country 313RE with my 7.3 diesel.

Not the same truck, but might give you a better idea of what to look for.

Love the manual transmission while towing by the way, especially in the mountains.