Rear Gears

[HemiXpress]

I am thinking of changing the rear gears from 3.21(open diff) to 3.92(LSD). What are the pros and cons of doing such? How would MPG be affected?

Thanks

 

[pressurepro]

Might as well go with 4.10 or 4.56 if your going thru the trouble.....mile per gallon or so...who cares its a truck..lol

 

[Hemi450hp]

Pros:
Better Acceleration
Better Towing Power
Faster 1/4 Mile Times
Better Mileage in Town
Better Traction with LSD

Con:
Slightly lower mileage on highway

 

[sicmadek]

I am thinking of changing the rear gears from 3.21(open diff) to 3.92(LSD). What are the pros and cons of doing such? How would MPG be affected?

Thanks

I went from 3.21 open to 3.92 lsd 4 months ago and its a whole new truck. I gained mpg in the city and highway. I only lost about 1 mpg on the interstate.

 

[HemiXpress]

I went from 3.21 open to 3.92 lsd 4 months ago and its a whole new truck. I gained mpg in the city and highway. I only lost about 1 mpg on the interstate.

Did you go through Dodge for the change or aftermarket? Did you recalibrate your ECM with a tuner or did Dodge do it? As their is no tuner option available for 2015 yet.

My dealer quoted me 2986.00 which includes -- Gear kit, differential, and 2 axle shafts. This does not include seals and bearings.

My thinking that their was just a whole LSD assembly that included the housing, ring and pinion and such was available that just went into the rear axle housing.

He also stated that I could look for a totaled 2013/14 Ram R/T. But he doesn't know if anything in the suspension or rear has changed for 2015.

 

[Pull Ya]

Moe's Performance sells gear sets and install kits, why not check with Matt.
Jay

 

[Hemi450hp]

Did you go through Dodge for the change or aftermarket? Did you recalibrate your ECM with a tuner or did Dodge do it? As their is no tuner option available for 2015 yet.

My dealer quoted me 2986.00 which includes -- Gear kit, differential, and 2 axle shafts. This does not include seals and bearings.

My thinking that their was just a whole LSD assembly that included the housing, ring and pinion and such was available that just went into the rear axle housing.

He also stated that I could look for a totaled 2013/14 Ram R/T. But he doesn't know if anything in the suspension or rear has changed for 2015.

Check out the pricing we have right now on these parts.

OEM LSD - $499
OEM 3.92 Gears - $349
Master Install Kit - $99.99

Total - $947.99 w/ FREE Shipping.

This is everything you need for install minus the fluid. Mopar is very proud of these parts, so they charge a small fortune at the dealership.

As for tuning, you do not have to tune for gears. The truck reads speed at the wheels and not the diff, so changing gears will not affect your speedometer.

 

[Booms]

As for tuning, you do not have to tune for gears. The truck reads speed at the wheels and not the diff, so changing gears will not affect your speedometer.

That's some good info right there!

 

[sicmadek]

I ordered everything from moes and had a local shopdo the install

 

[SFD213]

Depending on the tire size you have or are planning on getting, it might just be worth 4.10s or 4.56s. I have a 04 2500 so its a little different but it all comes down to ratios with the outer tire diameter. Almost everything ive seen on this forum has said go 4.56s and the guy who went to 4.10s love em but wished theyed went with 4.56. I know ill be going with 4.56s running 33s and then 35s. On 33s, 4.56 runs like a 4.10 on stocks and on 35s they run like 3.92s on stocks. With mpg boosts all around to compliment a serious jump off the line i cant see why not go with the 4.56