Hello Everyone,

I am in the process of getting a programmer for my truck. I just reciently put a 3in body lift withn 37" tires on my truck and my Hemi engine is *******. I need to figure out a way to help her out and help me get some gas mileage back! so i can save at the pump with my 34gal tank.... any help would be appreciated thanks!

 

what gears do you have in that thing? Sounds like that's what you'd need more than anything.

 

4.56's will definitely go a long way.

 

Gears and I'd pick up a spare CV half shaft, the lift and 37s puts a good bit of strain on them and one always seems to go at the most in-opportune time...

 

Take a look at the Superchips Sticky HERE but no tuner is going to get you drastically better mpg's. Figure 1mpg maybe 2mpg topps. That's $8 savings for an entire 34 gallons. You need 40 tanks before a tuner would e paid off. That's over $5,000 at $4/gal. So, when the gas price drops, you need even more tanks to make up the difference.
Bottom line...you signed your mpg's away when you bought the truck and again when you added 37" tires and lifted it. I have a 2008 and the transmission was mushy and soft and my truck felt like a dog even with 3:92's. I have since purchased a Superchips tuner w/trans package and will never go back. Truck shifts quicker and harder and feels very light on its feet as compared to before. It won't help you with towing a whole lot with 37" tires, but it'll definately improve your day-day driving.

 

The first thing you must do as mentioned before... GEARS! There is just no making up the difference when you added those tall tires without a gear change.

 

Alrighty thanks guys appreciate it big time... im kinda new to this whole thing if ya couldn't tell man but yall are a great help.... this whole tuner thing is kinda hard to grasp but if its gears i need that sounds like the plan... now another question. How will getting gears affect my MDS system?? And how much do you think it will run me??

 

Also as for gears i have the stock ones in it so that probably doesnt help me any ha ha ha.... so 4.56's are best?? is ther a palce i could go to talk to someone in person about what kind is best for my truck??

 

If your stock ones are 3.55s with 37" tires you have an effective gear ratio of a paltry 3.11 and I'm surprised you can even get out of your own way.
With the optional 3.92s you would be 3.44 which ain't a whole hell of a lot better.

Ideally for large tires, to balance power with fuel economy you want your final effective ratio to be between 3.9 - 4.1. So with 37" tires you would be at 4:1 if you install 4.56 gears, which is about perfect.

I've seen prices all over the place reported on the forum. $1600 is about the norm for good gears, a good master install kit with Timken bearings and labor. DO NOT cheap out on the install, AAM axles are a b*tch to set gears in. Find you a good, reputable shop that not only has experience setting ring & pinions but one that has done them in Rams.

I have a deal here with a good shop where they will do $600 per axle for anyone I send there.

If you have the stock LSD it would be a good time to replace the POS with a good unit from Auburn Gear or a Detroit TruTrac while they are in there...

And seriously, think about buying a CV axle and LEARN how to replace one, IFS front end trucks DO NOT like 37" tires, especially when using a lift that puts the CVs at high angles...

 

Awesome info. really appreciate it.. so where do u happen to live down south that sounds like a heck of a deal for 600 an Axle might be worth the drive.... hmmm or may b not.... so how does the computer on my truck recognize the new gears ???? would i still have to get the Programmer. Oh and as for the MDS is that totally out of the question once i install the gears???