2014 and up gear swap

TWILLIAMS9 · May 20, 2015

Yeah I do I usually average about 12-13 on highway driving 65 and in tow. About 9. My overall mpg is usually 10.5-11. Before the lift and tires I was about 13. And that was with only 2500 miles on the truck. I have about 8700 now. Hoping to get close to where I was. The MDS should be able to kick on with the new gears at highway speeds. The only time it comes on now is if I'm below 45 mph.

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KarL45 · May 20, 2015

Just wondering why the gear change. Towing or racing? Laugh, but if your looking for 1/4 mile performance, would truly think about something like the 4.88. Wouldn't do that for towing as I feel the reduction of ring to pinion contact would be a little light for heavy towing wear.

regularcab2500 · May 20, 2015

Good luck man!

TWILLIAMS9 · May 21, 2015

KarL45 said:
Just wondering why the gear change. Towing or racing? Laugh, but if your looking for 1/4 mile performance, would truly think about something like the 4.88. Wouldn't do that for towing as I feel the reduction of ring to pinion contact would be a little light for heavy towing wear.

The gear change comes because of a few reasons.

1. To get back the power I lost with the lift and tires

2. To gain a little mpg and allowing the MDS to actually kick on.

3. I'm looking into getting a travel trailer soon and I will be towing it up into the Sierra Nevada mountain range where we like to go camping.

I'm hoping there is a noticeable difference from now to the 4.56. Hoping it feels like it was when it was stock, and if I can gain an MPG or two that would be much appreciated. We shall see I guess. Regardless of mpg numbers, the return of the usable power will be a welcomed return, especially while towing in the mountains.

I originally was looking for 4.88, however, they do not fit our front axle. The 4.56 should put me back to stock and I am totally okay with that.

TWILLIAMS9 · May 21, 2015

Does anyone know if the regear will affect any speed sensors or ABS? The shop told me that the Fords and Chevys have to have a programmer to get the new gears to work without any lights on the dash going off. The shop wasn't sure on our current trucks as they haven't done one yet.

webdogg · May 21, 2015

I'm guessing it will throw your speedometer off. Pretty sure it did on the 2nd gens.

TWILLIAMS9 · May 21, 2015

The way I was thinking is if it would actually be back to being right since I have the larger tires and the new gear set puts me back to stock ratios. I just don't want any indicator lights on my dash.

loveracing1988 · May 21, 2015

You will be fine as far as the speedometer goes. You shouldn't have any lights either but that I'm not sure of. Since someone has already put 4.56 gears in their 2014 with no issues I would say you are fine.

TWILLIAMS9 · May 21, 2015

That's good to hear, however I'm still nervous.

Broke pilot · May 21, 2015

As long as your speedo is correct within a few mph you'll be ok ABS wise. It usually only freaks out if there's a miscommunication between rotation speed of the tire and the trucks estimated speed in the computer. Basically your abs wouldn't ever know when to help because it thinks the truck is going XXmph when the wheel speed sensors show it's going XXmph and then the truck is still moving (if you have bigger tires).
Did you have your speedo corrected after the 37's? If not, you'll be fine, no lights now, there won't be any after a gear change. Like I said above you're in more danger of the abs freaking out now under a hard stop than you will be after the gear swap. Have fun bud!

TWILLIAMS9 · May 22, 2015

Just dropped the truck off. I'm pleased that they will be installing OE gears. Truck should be done by the end of the day.

Gears for the front.

webdogg · May 22, 2015

Can't wait to hear first impressions. At some point I'll hopefully move up to 4.56.

KarL45 · May 22, 2015

As far as speedometer or anything else, when changing gears it's plug and play. Speed is gauged off wheel sensors. Changing tire size though will require a re calibration.

TWILLIAMS9 · May 22, 2015

Here's some pics as they tore everything down and pulled it out, incase you guys wonder what the inside of our axles look like.

ImageUploadedByTapatalk1432316790.893035.jpg

Front diff

ImageUploadedByTapatalk1432316803.094047.jpg

Rear diff

ImageUploadedByTapatalk1432316850.295486.jpg

ImageUploadedByTapatalk1432316861.648556.jpg

ImageUploadedByTapatalk1432316878.699543.jpg

Sent from my iPhone using Tapatalk

TWILLIAMS9 · May 22, 2015

Well there is a big problem with installing these gears. I was under the impression that my rear end was an 11.5 which is what my build sheet says. However, the shop gets into the rear axle and lo and behold it's an 11.8. I called my dealership who says that my axle is an 11.5 but the 11.5 gears will not work this axle is an 11.8. I don't know how it's even possible. They have to get some different bearings to fit the axle and it will not get done til Tuesday. This is ridiculous!

regularcab2500 · May 22, 2015

Arent the 11.8" rear ends for the dually trucks?

TWILLIAMS9 · May 22, 2015

Exactly! But apperantly the internals are 11.8 products. The guy knows his stuff and he told me "I'm sitting here looking at it and I am telling you that 100% this is not an 11.5 axle. These 11.5 gears will not fit, they are too small. You have an 11.8." One hand I'm happy that I have a bigger and more durable axle but I am also very frustrated that they have too overnight parts from Washington and get t done Tuesday since its Memorial Day weekend.

regularcab2500 · May 22, 2015

**** me runnin i have the same rear end! Ask him if theres anyway to tell for sure without ripping the diff cover off?

TWILLIAMS9 · May 22, 2015

He said usually the 11.8 has the finned aluminum diff cover. So he assumed just looking on the outside that it was an 11.5 until he got inside it.

loveracing1988 · May 22, 2015

I hate to be the one telling you, but your guy is a moron. I work for AAM, I see the internals of these and the 11.8's every single day. The only trucks that get the 11.8 axle are duallys, we don't make an 11.8 in a srw variety. The 11.8 diff case and gearsets will fit in the housing of an 11.5 but either they sent the wrong gearsets or they ordered the wrong parts.

2014 and up gear swap

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