I have a 2004, 1500, 4.7, 4X4, MANUAL TRANSMISSION. I have the 3.55 gears and my tires are the stock 265's and don't plan on changing the tire size.

My question is- Would changing to the 4.56 gears with the stock tire size be to much? Or should I go with the 4.10's. I am changing mostly for the sake of towing. I don't race it and I am not a speed demon. I am mostly on a 55 MPH HWY. Towing about #6000. I noticed that most of the guys on here with 4.56's are running larger tires. Would my MPG suffer that much with the manual trans?

Also. Would a tuner do much for me having the manual? I thought they mostly just changed shift points in the automatic trans.

Thanks in advance for any answers guys.

 

Gears would help for sure, but 4.56's are a tad much. You will notice a good difference with the 4.10's. A tuner would help as well but not as much as the gears and in fact most tuners for our trucks do not have a transmission support setting for the shift points.

 

4.56:1 are the way to go... the overall drive ratio (which is the true concern as far economy relates) is barely effected.. but first and second? they ARE effected, and it's absolutely for the good..

furthermore, you're going to pay the same for either... do it right and don't have regrets.

 

A tuner will give you more power for sure and cost a lot less than regearing a 4x4. As for the 4.10 vs. 4.56 vs. stock, I'm not sure how worth the cost is when you could always just downshift. For example w/ your setup at 60 mph in 5th 4.10's put you at 1909 rpm but w/ the 3.55's you would be at 1653 rpm, but just downshift to 4th and you're at 2264 rpm. 4.56's at 60 mph in 5th are turning 2123 rpm. Here is a link to a gear ratio calc. if you wanna go through the numbers http://www.rearendparts.com/pages.php?pageid=16. Besides the cost you may also have to deal w/ gears that end up being noisy, it's hard to find a good installer for the 9.25 rear on the dodge.

 

Gears are the number one most effective mode to these trucks.. a tuned won't come close to it.. nowhere near it in fact..

Comparing rpm range to speed is misleading. Just as important is engine load. The engine, through use of taller gears, is working less to achieve the same speed.. you're not tossing gas at it that's not being burned, which absolutely kicks economy in high gear..

Gears are worth every penny... This isn't even going into the value added to saving stress on your tranny.. that is huge too..

 

You do know he has a manual tranny, all he has to do to increase engine load is downshift, so he doesn't have to lug the truck in a higher gear unless he wants to.

 

this is suggestive that the ratio difference between 4th and 5th gear, or even 3rd and 4th is less than the overall drive ratio in any gear between 3.55:1, 3.92:1, 4.10:1 or even 4.56:1 gears, when it's not..

the overall gear ratio is what is the concern. tire size plays THE central role in that.. fwiw, and not from what I've read but from my experience with three of the four ratio's:

from 3.55 to 4.56: off the line, in first gear the difference is massive.. noticeable the first time you apply ANY acceleration.. it is likely the equivalent difference in attempting to launch in two wheel drive, and four low. You get THAT much more punch to the terra.. Unlike four low, you don't red line... at the other end of the gearbox- as in fourth or fifth gear, the difference is just enough that your engine is bumbling along higher in the range- as in closer to the power curve.. as in less engine load without turning 1k rpm + as you would downshifting..

I personally wouldn't spend a dime re-gearing from 3.55 to 3.92.. 4.10 would be on the table ONLY if I spent most my time on the highway without any cargo of any kind.. the low down grunt would get our heavy **** truck in motion easier (less sustained load on the engine) but you could still enjoy the stupid low overall drive ratio these trucks are notorious for..

4.56 gives you a full third more power to the terra than 3.55's low in the gear box.. when your high in the gear box, your overall ratio is different by a marginal amount.. that marginal amount is just that when looking at the mechanics of ratio, but huge when looking at the weight of the truck it's moving, and the power plant in the truck it's moving..

the 5.9L Magnum produces torque and power in a much lower range than the 4.7, or 5.7.. the 4.7 and hemi start kicking hard at around 2400rpm.. if you can find a range of gears that keep you at that engine speed, and 'planed off' at that range (meaning not still trying to achieve higher engine speed, dumping more fuel than is being burned, or what is evident by vacuum pressure... long way of saying the engine is holding a steady speed) you WILL save fuel, and you'll have power just a little bit of pressure on the skinny pedal away, because your closer to the range that engine starts it's power band.

there is nothing you can do to your engine in terms of bolt-on's or programming that will achieve this.. you can re-cam, and select a cam that produces power lower in the range.. with an automatic you can match the torque converter to the cam.. you can run tiny tires that effectively lower your overall drive ratio.. the best way to do it- and it is just shy of the expense of having someone else re-cam your engine, is gears...

original poster: if you're going to re-gear, don't screw around with anything shorter than 4.10's.. 4.56's are optimum for the available R&P's in my opinion.. 4.88's are just starting to be too tall- especially on the highway.. If I had the ability to cut gears, I'd build a 4.35~4.4 and believe that perfect for these trucks.. you gotta understand that the makers of all auto's have cost at the top of their list of concerns.. the 5.7 w/3.55 was pushing it as it was in terms of power, and simply an effort to report better fuel mileage to the government- and realize, those quoted miles per gallon are NOT actual, but instead presented mathematically as a result of engine speed/gear reduction through the tranny/axle ratio/ stock tire size.. they don't account for engine load, though engine load plays likely the central role in efficiency of a rig.. they don't change rear-ends to match the power plant- they interchange them.. then they look for the numbers.. this is assbackwards, a TRUCK should be built precisely opposite.. primary duty/ ratio/ transmission/ engine... that doesn't benefit mass production though.

 

Well I've got an nv3500 in my truck and went from 3.55 to 4.10's and I don't think it was worth the trouble/cost. I don't tow a lot and am on the highway going 65+ mph a lot of the time which is why I did the 4.10 vs. 4.56, running the same 265 tire size as the OP. Best advice I can give is if you're towing a whole lot then it may be worth it, if it's just every now and then I wouldn't do it. It's a lot of dough for new ring and pinion for the front and rear diff., master install kits, and labor to have it all done. Then you also need to find a shop who actually knows how to do the install properly on the 9.25 rear, something I can't stress enough, this is the most important part of regearing your truck if you choose to do it.

 

Thanks for all the info guys. I did make one mistake I am running 245/70/17's not the 265's like I previously stated. Does this make a big difference?

 

You will be running about 70-75 rpm higher in 5th at 60 mph than the original numbers I gave you. How often are you towing w/ your truck?