Switching from 3.92 to 3.21...

[dts828]

Expensive, doesn't the front differential need to be changed also.

Sent from my GM1917 using Tapatalk

 

[Scram1500]

After owning both I see the positives and negatives of each. My driving is rural roads, hardly any highway, usually 45-50 mph. The average mpg is the same 16-17mpg. Only difference the 3.21 rarely made it into 8th gear and I used the brakes more going downhill. The 3.92 has more snap when you hit the gas and gets through the gears quick. I wanted to get 3.55 and live in two worlds at the same time but a paper pusher somewhere decided that option isn't available for Hemi's

 

[Jack]

I think you have me confused with someone else as I am not arguing against you or posted any logic.

What I will post is two window stickers that don't seem to suggest you get 4-5 more MPG with 3.21 rear end.

View attachment 66500

View attachment 66501

The EPA rating is tested on a 3.21 rear end. 3.92 is an at-cost option and thus not required to be in the EPA rating testing. Frankly 3.21 and 3.92 costs FCA the same, and 3.92 is an at-cost option for the purpose of getting a better EPA rating. Fun fact, the reason auto start stop is on by default every time you start the car is also due to EPA rating. EPA requires standard feature that most users prefer to be tested, that is if manufacturer has reason to believe auto start stop feature will be permanently disabled by a large amount of users if allowed, they'll have to test it with the auto start stop disabled as well.

 

[UnloosedChewtoy]

I wanted to get 3.55 and live in two worlds at the same time but a paper pusher somewhere decided that option isn't available for Hemi's

Yeah, they stopped offering it in the 2014 model year. My 2013 Ram was a unicorn with the 3.55 gears option, Hemi, and 8 speed (first year of the 8-speed being offered, most 2013s were 6-speed autos). Only owned it for a few months before a semi decided red lights are for losers, and tried to take me out. Only took out the truck though. Got a 2014 with 3.92s a couple months later.

 

[Wheeler]

Mpg gain will be negligible. Fun loss will be more noticeable. Had had 3.92 now driving 3.21. If you really want to change zautomotive Tazer will let you reprogram for rear end swap.

 

[Scram1500]

How realistic / costly is it to switch a truck that comes with the 3.92 gear ratio back to a 3.21?

I’ve found several trucks that I like that have the 3.92 instead of 3.21, but I do not need the 3.92 as I do not do a lot of towing.

I realize this may be a really stupid question.

Crazy idea, but work with me.... bigger tires will effectively change the gears. You just need like a 38 or 40 inch tire, oh and a 6 or 8 inch lift