I recently purchased a 2000 E250 for a work truck and find the gas usage a little hard to take. It's a 5.4 triton, automatic. It has a low howl in the rear differential which I'm having rebuilt and here's the question. Would it noticably improve the mileage by changing the ratio in the diff from the now 3.73 to a 3.55 or even higher. I don't tow with it. what other problems would I encounter by making this change?

 

What's your measured MPG?

 

Last check was 13 in town. It doesn't go far from in town. Maybe a 30 mile radius of home.

 

A small change from 3.73 to 3.55 is not going to help much. The cost of the gear swap will take years to pay off with the gas you save by making that change.

Try using synthetic oil in the engine, gear lube in the diff, and if you can afford it in the trans as well. It's possible to pick up 1-1.5 highway mpg with such a conversion.
Make sure the tires are aired up, check to make sure the rear brakes are not dragging.
Add an air dam under the front bumper. If it has a factory one add a bigger one. I made one the width of my front bumper using some plastic I picked up at my local home improvement store. It was a plastic used in place of wood house trim. 1/2 inch by 8 inch by 8 foot long. You can bend it by heating it with a heat gun, cut itto size with a saw. Attach a piece of angle iron to the bumper and the plastic to the angle iron. Costs less then $20.

 

13 is par for the course. Don't waste money and time with synthetics looking for more mileage, you'll run over a dollar chasing a dime.

 

I disagree. You have to use oil anyway and the cost of synthetic is only about 2 to 2 1/2 times the price of regular oil. With longer change intervals and the small increase in fuel economy the cost difference gets pretty small. I agree that on a van you may see a smaller increase that what I quoted, that was on a 302 in a Mustang. I tried this on a 1988 E-250 w/351 and saw a around a 1 mpg increase. The air dam added another 1/2 mpg. This was all at highway speeds and not around town driving.

 

....K.....

 

I think there is a mileage thread a bit lower down in this van forum--do a search. The change from 3.73 to 3.55 won't make a difference, really. In town, you may actually hit the overdrive gear a bit more quickly with the 3.73 ratio and it might actually get you better mileage than 3.55's.

I have logged my gas mileage for the full 80k miles I've owned my E150 and have changed to synthetic engine oil at about 60k miles. No gas mileage change there. Syn axle lube may help a bit, but I've got an Eaton posi in mine (I had it put in) and they recommend non-syn lube.

If you need to buy new rear end gears anyway, you could change over to a 3.55 but I'd guess your mileage would increase only a tiny bit and mostly on the freeway if you are on level ground and not heavily loaded. If the original gears are OK and you just need bearings and such, don't bother. You will have to mess with the speedo gears if you change.

My van will do maybe 1-2 mpg better than 13 around town, but it's an E150 with a 4.6 (and 3.55 gears) and is generally unloaded. I've had 3 other big vans over the years and 12-13 in the city is what they get...it's a lot of weight to get moving off a stop. Likewise they eat brakes as well.

What did you previously use as a work vehicle that makes you disappointed with the van's mileage? The EPA ratings on the E150 with 5.4 are probably something like 12 city and 17 freeway and the 250 is heavier.

George

 

I also have owned a few 3/4-1 ton Ford/Dodge/GMC vans over the years and no matter how I drove I got around 12-13 MPG in all of them. If I recall the diesel I had did slightly better but not much.

 

I try to drive like granny and use the old racing trick of removing all weight that's not needed and run max tire pressure and the best combined Ive seen is 15.5 mpg with my 4.9 six and 2.73 rear C6 tranny. in town I get 13.
My V10 E350 gets 11.5 combined. both vans are loaded with ladder rack, ladders, tools and materials.

I think your mileage is pretty common for a flying brick

 

If you are after drastically better mileage.... a Sprinter van is the route go... or wait a few years when the Ford version of that is out.

Why do you need a full size van?

 

My van gets about 10mpg, all city driving. You eventually learn to just deal with it...

 

This my first van and the largest vehicle I've ever own, by far. The first time I filled it up at the gas station I stopped pumping when it got over $80 and looked under the van. I was actually afraid the gas was just running out the bottom somewhere.
Live and learn.

 

I only get about 9.5 miles on my E350 with 5.4 motor and 3.55 gears doing all city driving. With my standard loadout of tools I am rolling about 6700-6800 lbs depending on how much gas I have. I would LOVE to see 12-13 mpg. You guys that are getting 12-13 mpg how much do you weigh with everything in the van ?

 

To get caught up with the replys.....My previous vehicle was a 06' F150, 5.4, with a heavy fiberglass cap. I averaged 16-17 mpg in town. All stop and go traffic. The only mod to the pickup was the MBRP cat back dual system. On the highway, running in the sweet spot where your not pushing the 5.4 but keeping up with traffic I got 20, sometimes better. I make many trips to Camp Lejeune in North Carolina and checked it everytime. The tool load is equal from the pickup to the van however in the van I only use the back half, with steel bins and shelves for tools. The front is used for cabinets and the like for my customers. I don't see the trade off with synthetics except for the duration of changes and agree the gear change may not do much based on initial cost and the long time for it to payback. So I'm going to consider the gear change question answered but move onto a dual exhaust system and a tuning chip or programmer. I think there's better mileage in any vehicle it's just finding the right combination of upgrades or changes to make it happen.