2004 2500 4x4 Hemi ext cab 8' box. 35" rubber, 3:73 gears.

First Dodge I've ever bought. I was a GM lifer. Bad taste in my mouth after last GM truck.

So anyways, picking the truck up in a day or two. I test drove the truck (first hemi drive ever) and was super impressed with the Hemi and especially how it drove, rode, handled, shifted and how much power it had with 3:73 gears and 35" rubber. I expected being all stock that the shift points would be way off ect ect.. but it was great. I know it hasnt been programmed because the bigger rubber was just put on it.

So......I'm looking at a muffler change (just for sound asthetics ofcourse)

But at the very least I would like to either :

A) reprogram shift points with a programmer that allows tires size/gear ratio calibration and shift points based on this WITHOUT being required to do a performance tune if I dont want to. Plus speedo recal obviously.
Im told this will help immensely.

OR

B) Just leave as is and go to 4:56 gears. Obviously WAY more $$ for this.

I want to optimize MPG as much as I can. If I can gain HP then great. Want to optimize performance for the tire size and gears is my goal.

I'm excited about this first dodge. Been dying for a solid axle truck without a tin foil frame.!!!!!

 

Well with 35s I would suggest getting the 4.56 gears first. That's a lot of rubber to get moving with anything less than a 4.1 ratio.

 

+1 on the gear change. You will be much happier with the truck afterwards performance wise. Then later on down the road get a programmer

 

Maybe wrong but i don't think a gear ratio calibration is needed either.

Also like you mentioned.. 4X4 = double the R&P and double the labor if not DIY so the price may get up there.

 

The gears will give you more "leverage" to get you moving...and the engine won't have to work as hard like it would with a taller (lower number) gear especially if you use it for towing. So that should actually help mileage somewhat. Plus with the double overdrive ( 4th & 5th gears) highway mileage shouldn't go down.

 

BOTH will yield big advantages in performance but MPGs - sorry, you have a 3/4 ton truck running 35" tires with a 345 HP V8 - sorry - MPGs ain't gonna be a strong suite.

Tuner may net 1 mpg overall but will take the performance tune to do so, so after calculating the higher cost of premium fuel, you won't gain anything but better performance and improved shifting. Gearing will probably see a solid 2 MPG in town but on the highway you'll be about where you are now at best and may give 1 or 2 MPG back since you'll be running higher RPMs...

 

Ledyard, I noticed this was your first post, take what Hammer has to say to heart, he is kind of the unspoken king of the forum, this guy knows his $h!t.

 

This is why I joined a dodge specific forum. Thank you for the solid advice! ALL OF YOU. I had a feeling gears would be the answer. I do actually have the cash to get the gear swap done. I just got a quote for the 08' chevy 1500 that I decided to get rid of instead of putting money into a half a truck. I assume their pain in the *** front end would be more labor intense? But the closest guy to me is the only guy in my area that specializes in differentials only. It's all they do. He quoted me $1950 parts, labor, tax included to go from 3:73 to 4:56 on my chevy. I know that's steep. But he comes highly recommended so whattya gonna do.... I'd only need to drive the truck a week or two before I could get the swap done.

Does anyone know what my rpm would be highway at 75 mph? That's what it would be for any highway driving which is once or twice a week 70 mile round trip. Other than that its 4.5 miles to my business from home, 3.5 to my gym and any stores so its gonna be a lot of county road driving on hills and such.
I'm frothing at the thought of the extra ***** that will come with the 4:56 gears.

Also....by just going to 4:56 with 35" tires that should basically return it to stock no? Meaning the shift points and speedo should be closer even than they are now right? Then when I get more $$ I can get a programmer to optimize everything a little finer I assume.

Thanks again guys. And if anyone can reccomend a good front leveling system to go with that'd be great. I assume shocks would be needed too.

Btw im in. Central NY if anyone knows a better deal on labor for gears.

 

You will definitely benefit from the programmer, it should bring everything together nicely. I have a 2500 platform and I went with the Hell Bent Steel 2.5" leveling kit with 35" tires, looks awesome. I also replaced my shocks with Bilseins all around for a better ride.

 

The 4.56 with 35" tire would be close to a 4.1 with 31" tires. Your speedometer would be off by about 10% if you re-gear assuming your previous tires were 31" tires. Your speedometer would be off now by about 13% with your current gear going from 31" to 35" tires. I think in either case you will want to reprogram to correct the speedometer. A dealer service could do that if you don't want to by a tuner. Now actually the tires are not exactly 31 and 35 in diameter so the bottom is not exact.
Comparison 35*3.1415/4.56 = 24.11 in/rev of driveshaft
31*3.1415/3.73 = 26.11 in/rev of driveshaft
Current 35*3.1415/3.73 = 29.48 in/rev of driveshaft
31*3.1415/4.10 = 23.75 in/rev of driveshaft