Just bought a 2003 Expedition. I use it only for towing my 26' 7,000 lb. camper. It has a 5.4 with 3.73 rear end. I'm only getting 7 MPG. I'm told that changing the rear end gear will improve gas mileage. Which gear would be best the 4.10 or 4.33.
I've also considered an air deflector but have read that they aren't worth the money. Any ideas or suggestions would be greatly appreciated. Thanks, Jim

 

Your going the wrong way with the gear selection if you want to improve your gas mileage. Also I hope your not getting 7mpg while not towing anything? If so I would take that thing back to the dealer.

-Brian

 

I guess I didn't explain my question well enough. I use the truck exclusively for towing a 7,000 lb. trailer. I am not concerned about MPG when I'm not towing. My last truck had a 4.6 with 3.55 gears and got 5 MPG while towing so I know I'm going in the right direction.
So fellow campers, what rear end are you using and what kind of MPG are you getting?

Jim

 

Hi Jim

I agree..4:10 will not increase your mpg. Solo or towing. Thats just a fact..at least it didn't for me w/my Jimmy 6cyl and 4.10s..but it was a screamer/puller!

However...are you sure w/mpg? On moded. 99 F250LD 4X4 4.6L a/t and 3.73...worst towing w/approx. 11000#+ GCWR was 7/8mpg...best flat not hills in o/d was 10 1/2 mpg consistent. Of course thats between 55/60mpg. Faster..ALOT less.

Geez...how fast do you tow?

How many miles do you tow per year? Seems to me thats a determining factor. Add ons for mpg may/maynot be cost effective? For me over the years..most ive tried were not. Althou schip/k&N/cat. back..i got 1 mpg increase w/91+oct..not cost effective for me...but the increase in hp/tq sure helped when towing.

The air deflector...is that the one that sits on top of cab to deflect wind up/over front of TT? If so..there again...cost effective maybe/maybe not..but alot depends of frontal (wind drag) area of TT. Some tow rigs use them.

I havent used one...maybe someone here has. So keep checking.

Heck...i got better mpg w/my old 88 F250 w/460. GVWR 8000# maxed out + some ..worst was 6 1/2mpg.

Good luck....OT

btw...if $$$ no problem...get every mpg gizmo on the market

 

Since a #7000 camper is about the max for your truck, like OT said, I'd say you are not going to get much improvement on mpg. Gears will help your tranny live a bit longer IMO. You can mod the heck out of the motor and it'll tow better, but I don't think you'll see the mpg gains.

I only get 9 mpg with a #4500 camper. I've got a 5.4 and 3.55 no mods, just an exhaust / K&N filter combo.

Just watch those tranny temps. I just installed a tranny temp gauge, and man, that thing gets hot fast when it's working.

Good luck!

 

I get similarly low mileage with my 5.4L and 3.73 gears when towing my 6,000 lb. trailer. And the faster I go the worse the mpg. It's physics.

I don't know of a "cost effective" method of improving your mpg, other than reducing your load and speed.

Dino

 

How fast do you drive? The difference in milage seems to get greater as speed increases. I get about 8MPG and try to keep it below 70MPH. I tried doing 80 for a while last summer and had to stop for gas in about 2 hours instead of 3. I did not record the milage though. I have a K&N air filter they help a little with milage and a little extra horsepower. I have always used a K&N for towing and gain about 1MPG. I do have a wind deflector but don't use it as it will not work on the pickup. I have used it for a van where it mounts on the back and close to the trailer. I saved about 1 MPG with it. A coworker has borrowed it a number of times for his Expedition and 26' trailer and claims to get about 2MPG more.

 

Thanks for the input. From your responces I can see I'm not alone. I talk to the guys that have motor homes with 500+ cu. in. engines. Most tell me they're getting 10 to 12 mpg. I thought if they're getting that good of mpg I should be getting better than I am. I don't know how they do it.

Thanks Again, Jim

 

Jwill1, I'm posting a little late with the other responses, but... Those motorhome guys are pullin' yer chain. The best mpg I have ever seen in a Gas motorhome is 7-8. I have put approx 20,000 miles on a 37' pace arrow with the 6.8 Triton V10 and 5.29's averaging 6-7!

My 4x4 ORP Supercab 5.4 auto F150 gets in the 6-8 range at 70 MPH towing all of 8,000 lbs*.

I have the 17" wheels and 3.55's I'm far worse of (ratio wise) than you are. But the F150 weighs a bit less. I have found that keeping the back end from sagging badly is worth >1 mpg.

*weight distributing hitch, sway control, and awesome trailer brakes.

 

I get about 300 miles out of a 25 gallon tank of gas or 12mpg while towing a #5500 5th wheel @ 55mph. I get about 200 miles out of a tank going 65mph+ or 8 mpg.

 

air resistance quadruples if you double your speed. that is, there is 4 times as much air resistance at 60 mph as there is at 30 mph. so speed has a HUGE effect on your gas mileage; especially when pulling a trailer with a large frontal area. no boob jokes please : - )

 

I tow a 6500 lb 5th wheel with my 97 F-150. I changed from the 3:08 rearend gears to a 3:55. Gas mileage went from 17 to 15 while not towing and I get 10 when towing.