Gear Ratio Change

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Oct 15, 2016 | 06:52 AM

#16

brickman

More Turbo

Joined: Apr 2007

Posts: 631

Likes: 13

From: Southern Ontario Canada

Quote:

Originally Posted by airm4n

I changed my 2011 f350 KR from 3.73 to 4.30. I found to me that it made a big difference and am still really enjoying it. Nothing else was needed just the gear swap and drove away a happy camper.

Did you do the swap yourself? How has the truck changed , mileage, power etc?

Oct 15, 2016 | 02:16 PM

#17

airm4n

Senior User

Joined: Jan 2015

Posts: 397

Likes: 7

Quote:

Originally Posted by brickman

Did you do the swap yourself? How has the truck changed , mileage, power etc?

Paid a shop to do the job maybe someday i'll learn but I have niether the time or the tools or currently the smarts

to do it. Dropped about 1 to 1 1/2 mpg for me from around 14 to 14.5 avg down to around 12.5 and higher if i keep the speed down but it really added a lot to the low end pickup. Takes off like a rocket ship and doesn't feel like everything power wise is over 3k rpm.

Oct 15, 2016 | 07:27 PM

#18

SportCustom

Cross-Country

Joined: Jul 2016

Posts: 62

Likes: 0

Quote:

Originally Posted by airm4n

Dropped about 1 to 1 1/2 mpg for me from around 14 to 14.5 avg down to around 12.5 and higher if i keep the speed down but it really added a lot to the low end pickup. Takes off like a rocket ship and doesn't feel like everything power wise is over 3k rpm.

Great before-and-after report of a gear change. Your real-world experience might be useful for those who have questions about running 4.30 gears, either before ordering or for a gear switch like yours.

Does a gear change need to be followed up with a speedometer/odometer correction on a SD, and if so did you do this? I ask because, on average, the forum wisdom seems to be that there is little difference in fuel consumption between 3.73 and 4.30 gears in a SD. Stop-and-go actually benefits from the 4.30 gears with less throttle needed. At highway speeds the 4.30 gears help punch through the air wall in front of the truck and a trailer with less engine load. The conventional wisdom may have to be reconsidered, at least somewhat!

Oct 16, 2016 | 01:59 PM

#19

WyoBull

Laughing Gas

Joined: Mar 2016

Posts: 1,033

Likes: 105

From: Casper, Wyoming

Quote:

Originally Posted by SportCustom

My truck is a 6.2 with 4.30's. My wife and I made a round trip to Denver on Friday, a little over 500 mile round trip. Cruise control set to 70 mph the entire trip and was running empty. Bucking pretty strong winds the entire trip. Broke 5000 miles just before getting back into town. Got worse mileage on the trip down and better on the trip back. MPG for the entire trip was 14.7.
I have done this same trip before but without the wind and got about 1.5 mpg's higher but cannot remember now exactly what they were.
The fuel savings of having 3.73's on a monthly, yearly basis is negligible and I will take the 4.30's every day of the week.
That is just my experience.

Oct 18, 2016 | 03:52 PM

#20

dirty1

Tuned

Joined: Feb 2006

Posts: 273

Likes: 0

From: MA

I am considering the gear swap, but I am not sure if the quote I was able to get is way too high. What is the ball park people have been paying for this?

Oct 18, 2016 | 07:34 PM

#21

82_F100_300Six

Cargo Master

Joined: Jun 2008

Posts: 2,875

Likes: 30

I would figure about a thousand bucks per axle if you are getting it done full service

Oct 20, 2016 | 09:18 PM

#22

RainDesert

Cargo Master

Joined: Jan 2015

Posts: 2,824

Likes: 39

From: Boise

Quote:

Originally Posted by dirty1

I am considering the gear swap, but I am not sure if the quote I was able to get is way too high. What is the ball park people have been paying for this?

My dealer was at $2800 which is right in there for a dealer.

Nov 20, 2016 | 08:05 PM

#23

82_F100_300Six

Cargo Master

Joined: Jun 2008

Posts: 2,875

Likes: 30

Im thinking a lot of folks will blow an unlimited amount of money on stuff for their truck but then not change their gear ratios. Because I see tons of new shiny trucks with big lifts and wheels and tires bogging down trying to leave a stop sign.

. I get maybe they've already spent so much money the last thing they want to do is spend thousands more. Or maybe they're freaked out doing something to their truck like that?

Today I was outside and a real pretty black GMC went by lifted super nice wheels spacers the whole shebang. But then when it took off from the stop sign it was lugging its *** off.