I have a 2018 F-450 that I use for a welding rig. Was wondering if it's possible at all to change gears out to a 3.73 or something like that to achieve better mpg? I've heard mix things so far. Or not worth the headache for a few mpg. I knew what i was getting into when I bought this but can't hurt to ask.

thanks for all the answers. Think im just going to slow down a bit instead, maybe try bit larger tires.

 

You can. Two gear sets, two master rebuild kits (bearings, shims, etc.) and labor... $2k - $2.5k.

Just have to judge if that's worth it. Fully loaded welding rig, I'd prolly rather have the 4.30's.

 

For all the cost and hassle, doubt the change would ever pay for itself.

 

Not everything is return on money. Maybe they just don't care about the gearing of the truck.

 

If you can find an entire carrier out of an F350 DRW with 3.73s with axle shafts you could swap it in. The M300 in the F450 has 41-spline shafts vs the 37-spline shafts in the F350. Front axle carrier split is 4.10 and up or down also but axle shaft splines are the same.

 

bigger tires will change your effective ratio

 

Read what he wrote, he is looking for better fuel economy, so it is about return on the money.

 

Everyone wants better mileage or at least they think they do.

Big heavy fuel sucking machines. It's the price we pay.

 

How many miles annually do you travel? Ultimately you're probably talking fractions of an mpg in improvement and if youre paying someone to do the install itll take over 60,000mi if not much more to even come out of the red and actually take advantage of the mpg increase.

Just using my own averages of 40,000mi annually and at best 1mpg difference between similarly grossing trucks 4.30 and 4.88, it would take me almost a full 2 years and 80,000mi to come out of the red having a shop swap my 4.88s to 4.30s. All this going by todays fuel prices and a parts and labor bill of 2.5k-3k.

 

My 2014 F-350 averaged about 15mpg empty; my 2022 F-450 averages 13.45mpg empty; both had 6.7 diesel. The savings in fuel would be 7 gal per 1000 miles. At $3.50/gal the savings would be $24.50. By my calculations, it would take 102k miles to break even if it cost $2500.

 

Slow down! 68mph in my 10,000 fat girl, she'll get 19.5mpg hand calculated. Under 2krpms is almost 20mph. At 2100 it drops to 11.7-12mpg, yes that fast.
run under 2k rpms and save fuel money.

 

If you’re running it heavy all the time. Regearing it to 3.73s might cause it to run a gear down and not increase the mpg anyway.

Either just drive it slower to increase mpg or maybe put larger diameter tires on it to change the ratio or both.

 

Yep, easiest and most cost effective change is to lower your highways speed.

 

Most of the guys I've ever known with their truck set up for a welding rig, their worst thing killing their fuel economy is all the idling they do, most don't put that many miles on their trucks.

 

Yeah for the cost of the gearing swap, it would take a LONG time to recoup the costs, especially since OP is using it for a business. He'd better be married to that truck for a LONG time.

Personally I'd just knock a few MPH off my cruising speeds.

I can somewhat speak to this. We used to have a place about 2 hours away on the expressway. In my old 'Wagon, running 75 mph (the posted speed limit) empty, I'd get about 11 mpg (4.11's in a brick powered by a 6.4 with a 6-speed). Dropping to 70 for the same trip in similar weather got me about 13.

Slowing down is the easiest, fastest, and cheapest way to get better MPG. You don't have to do any work, the results are immediate, and it's FREE!