ASking this question for a friend. He will be towing a 14,000 lb fith wheal, Truck will be a 2005 or 2004 f-350 crew cab dulie, with a 8 ftbox., 6.o power stroke.
Automatic

what rear end ratio would be better, a 3.73 or a 4.10, or othier ?

Most towing will be done on the high way, verry lilte hills, or mountian pass's, average speed 60 to 70 mph depending on road conditions.

What chioce willl allow this truck to get the best M.P.G possible and be less strian on the engine?

Thier is no need to go drag racing. Thanks for your input.

 

I don't think that your friend will get significantly better fuel economy for trade of possibly more wear on the engine/tranny and less performance on a fully loaded F350. I'd go with 4:10's, even ignoring performance.

 

4.10's.... MPG..... That's what OD is for and it'll be able to use OD more with the lower gears IMO.... I imagine it'll take quite a bit to get #14000 moving from a stop or up a 6% grade.... Having as low as a gear could only help that....

Towing that much weight, I'd consider the 6 speed manual as well.... If that's not an option, get a BIG trans cooler and a REAL tranny temp gauge.... The stock Ford gauges are nothing more then idiot lights with needles on them... Don't tell you squat for actual temps....

MPG would be lower on my priority list then strain on the drivetrain too.......

 

Check out latest "Truck Trend" mag. In it they talk about gear ratio's. Breifly they said from 3:42 to 4:10 there is about .04mpg less.

 

I'd take .04 mpg.

Heck that could add 25% cruising range when towing 14,000 pounds.

 

Thank you for the input.

 

One more question comparing the 3.75 to the 4.10.

Will the engine have more wear and tear on it with the the lower, or higher rear end over the life of the truck?

I understand the 4.10 will get a load moving quicker than a 3.73, but are you limiting engine R.P.M with the lower gears?

I'm trying to figure out if you need the engine torque R.P.M. or the gearing to tow.

 

My viewpoint is a bit stronger. I buy the lowest gear (highest numerically) that is available in any vehicle that I purchase. Your mileage, rpm, and wear difference will be so minimal, that it's not worth considering for a tow vehicle. You could eliminate the difference with a tire swap. I would buy the 4.10s in a flash if I never towed anything, much less if I was towing a 14,000lb. behemoth. Mitch hit the nail on the head..."that's what OD is for"...People ran similar ratios before OD was even available.

 

I would go with the 4.10 gears as mileage won't be much differance and you can get a big load going better with the 4.10 gear.

 

The realistic difference with that load is going to be 9.5 versus 10 mpg. I would trade that .5mpg for the added throttle response any day. ---go with the 4.10s. And make sure he gets the limited slip rear!

Just MHO,

Sidewinder

 

Test, sorry guys

 

hands down.......go with the 4.10 !!

 

So 2 questions then.

1) Where do I get these gears.

2) Who will install them for me? The dealership or is this a specialty shop job? There's a lot of glorified shade tree mechanic shops around here that I wouldn't trust to change the air in my tires.

Russ

 

rksylves, this thread was about ordering a new truck and simply checking off on one gear or the other.

That's a far cry from changing a done deal that you are already driving.

I'd think long and hard before I dropped that kind of money for less than 1 mpg.

(I've heard it's in the neighborhood of a grand)

I'd buy a wing for $500, $480 worth of stickers and a case of beer.
I'd drink the beer then put the stickers on.