Gearing question
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Mountain Pass
Joined: Jun 2010
Posts: 249
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From: California
Gearing question
Looking for a quick education. What do the different rear end gear options actually do for the truck? I know that with a higher gear ratio (i.e 3.73 vs 3.55), there will be worse fuel economy but better towing performance. Do the higher gear sets enable the engine to work less over time?
If you buy a model where 3.73 is the highest option, is it relatively simple to upgrade to 4.10?
If you buy a model where 3.73 is the highest option, is it relatively simple to upgrade to 4.10?
Junior User
Joined: Jan 2010
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I would have to say the the 3.73 is the better option when buying a truck. You might see a 200 RPM difference vs a 3.55 when in overdrive on a stock truck. Gas mileage is a non issue, prob. not worth worrying about on a stock application. The 3.73 does give you better towing ability and if you're planning on going with a bigger tire later on, it will help with that also. The limited slip rear is what I'm used to and it performs well, I don't have any experience witht the E-locker from Ford yet. Upgrading to a 4.10 gear in a 4x4 is a little more involved vs a 2wd because it will cost you twice as much due to having to change both front and rear gear sets. The engine will have to work less due to the gear advantage. But this is from a take off or when attempting to pass. Your trade off will be less top end speed for better acceleration. Also the higher gear will make you turn higher RPM's which will affect your gas mileage, but mostly at highway speeds. Hope this helps.
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Mountain Pass
Joined: Jun 2010
Posts: 249
Likes: 14
From: California
Thank you fasttimez....I was just looking to understand it more from a mechanical perspective. I was planning on going with 3.73 at minimum and have never changed a gear set. Sounds like higher RPMs and better low end with a higher gear set. Sounds like the engine may work less overall towing, but work a little harder overall (not that 200rpms is that big of a deal)
Junior User
Joined: Jan 2010
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I wouldn't say the engine works harder overall. Only at highway speeds will it turn higher RPM's, my 2010 4x4 with the 3.73 will see about 1,650-1,700 Rpm at 70 mph, my friends truck with 3.55 see's about 1,550-1,600 at the same speed, but these are with stock wheels and tires...it's not an issue in a stock application. Now when people start putting like 4.30 and 4.55 gears because of lifts and extremely bigger tires like 37's, then you will see your gas hand move when driving...lol
Postmaster
Joined: Jan 2009
Posts: 2,544
Likes: 4
From: Suffolk, VA
You kind of answered your own question. Think of it like a 10 spd bike. If you hooked up a trailer to the bike you'd put it in a lower gear. But you'll pedal faster to go the same speed. It will actually make the engine work less hard, but at the expense of increased rpm and less mpg. This is why the 3.73 is required for the max tow package.
