4.10s or 4.56s

[Fishstickz]

On the stock 3.55s my v6 hates headwinds. In fact, pretty sure it hates anything except a tailwind cuz it upshifts into third gear all the time. Not sure who the birdbrain was that thought 3.55s would be even remotely acceptable for a shrimpy 210 HP motor to push a 5,000 pound truck around, but I hope they got some help from their local mental institution.

Anyways, In the long run I'm wanting to get 35's and a 4ish inch lift. So before I get those, I'm wanting to upgrade the rear gears to be able to handle it. My main concern with 4.10s and 35s is the truck will lug and upshift all day long with a headwind or small inclines with bigger tires. The 4.56s I know won't have that issue but I don't want to overgear and watch my MPG drop even lower than I'm sure it already will lol

I put the numbers in a calculator and the 4.10s with new tires give me an 80 RPM increase to my current setup, and the 4.56s would give me a 300 RPM jump. Pretty sure the 4.56s will help get into the v6's wonky powerband better than the 4.10s


Anyways any outside opinions would be pretty appreciated

 

[RoadRamblerNJ]

4.56's all day long! You won't regret it.

I have a 2500 CCLB 4X4 6.4 with 4.10's and I'm going to either 4.88's or 5.13's. With my add-ons, my truck is 7,000 lbs +/-.

Don't waste your $$ with a small jump from 3.55 to 4.10. It will not be worth it. Once you go to 35" tires, you will need those 4.56's or even 4.88's.

 

[Fast69Mopar]

What is your daily commute like? Long highway miles or is it city streets with stop lights?

What is your cruise RPM at 65mph now? 70mph? 75mph?

If you decide to go with the 4.56 gears and you don't put the 35" tires and lift on at the same time, your cruise RPM is going to be pretty high with the 0.69:1 4th gear. Your driving habits on the big roads will have to be a tad conservative to keep that 3.7 from winding so high while cruising. Engine rpm at 70mph with a 31.5" tire is going to be about 2400rpm.

If you can slow down a bit to keep the engine rpm down while cruising the interstate then I say go with the 4.56's and be done with it.

I'm saying this so you'll know what to expect with the gear change. It will definitely help the truck get rolling easier from a standing start.
I'm all for low gears. Don't get me wrong.

Good luck and happy gears!

 

[Marley]

4.56 gears seem to pair well with 35" tires in most applications regarding Dodge trucks.
Jeeps tend to go lower, especially the 42RLE in Jeep TJ'S where 4.88 or 5.13 is the norm running 35's.

When the wife decides she wants a bigger trailer I'll be re-gearing to 4.56 in my Hemi with 35's.

 

[Fishstickz]

What is your daily commute like? Long highway miles or is it city streets with stop lights?

What is your cruise RPM at 65mph now? 70mph? 75mph?

If you decide to go with the 4.56 gears and you don't put the 35" tires and lift on at the same time, your cruise RPM is going to be pretty high with the 0.69:1 4th gear. Your driving habits on the big roads will have to be a tad conservative to keep that 3.7 from winding so high while cruising. Engine rpm at 70mph with a 31.5" tire is going to be about 2400rpm.

If you can slow down a bit to keep the engine rpm down while cruising the interstate then I say go with the 4.56's and be done with it.

I'm saying this so you'll know what to expect with the gear change. It will definitely help the truck get rolling easier from a standing start.
I'm all for low gears. Don't get me wrong.

Good luck and happy gears!

Right now with the 265/60s 65 is about 1650 RPM (+/- cuz the speedo hasn't been calibrated for these tires). Other than the 20 mile drive into town on 4 lane highway, it'll be mostly city streets and county roads. Occasionally I'll drive to OKC and back (about 150 mile round trip) but that's pretty rare

I'm thinking now to get the wheels and tires first to avoid the cruise speed of tall gears on tiny tires. I'm sure the 3.55s can survive a for a bit with big tires, may just get an upgraded tranny cooler to keep the temperature down. Plus I need some extra time to decide whether to get a locker or limited-slip or not. I'd love to have them but I'm not sure if its worth the extra $$ for me.

Jeeps tend to go lower, especially the 42RLE in Jeep TJ'S where 4.88 or 5.13 is the norm running 35's.

After reading this I may really need 4.56s. The RLE came with the later model trucks with a V6 including mine, and I know they have a problem with grenading when overheated. I've always wanted to get a bigger tranny cooler and I may just get one before I get gears and tires. I figure I won't be doing enough driving to get the tranny temperature that high but ya never know

Anyways, I got two estimates today, $1400 for Motive gears and a positrack (dont know what brand) from a diff shop, and 4 Wheel Parts estimated $1700 for G2 gears and an Eaton Elocker. I think I can get the gears installed for about $900 if I ditch the idea of a locker or LSD. Not sure how these prices compare to anywhere else

 

[Marley]

Around here it's $ 1200 per axle with warranty using Yukon gears.
Didn't see in your original post if truck was 4X4.

 

[HemiLonestar]

4.56 gears seem to pair well with 35" tires in most applications regarding Dodge trucks.
Jeeps tend to go lower, especially the 42RLE in Jeep TJ'S where 4.88 or 5.13 is the norm running 35's.

When the wife decides she wants a bigger trailer I'll be re-gearing to 4.56 in my Hemi with 35's.

You'll enjoy towing better with 4.56's...not so much the drop in mileage though lol

 

[RLJ10X]

My current 2011 has 4.10s and the 5.7, on stockish size tires. For general purpose, all around use, it's hard to beat 4.10s if you have the 545RFE.

But if you have a smaller engine, and taller tires, you definitely should go 4.56. I'll predict that you'll like your truck a lot better after you regear. If it was me, I'd do gears, then tires.

 

[Fishstickz]

Around here it's $ 1200 per axle with warranty using Yukon gears.
Didn't see in your original post if truck was 4X4.

Doesn’t look like i can multiquote on my phone

Anyways it looks like the price around here isn’t extremely expensive compared to everywhere else, i’m not too worried about the price as long as its not $500 bucks more expensive here compared to a couple of hours down the road

Also yeah i got a 2wd so it’ll just be the back diff


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[Fishstickz]

You'll enjoy towing better with 4.56's...not so much the drop in mileage though lol

Lol my worry is I’m already getting 15 mpg with my v6..I’m starting to think I’m running rich cuz I remember a time when I could get 17-18 mpg on a tank. O2 sensors maybe?

Besides that if I could keep my tranny from shifting into 3rd so often I know it’d help the gas mileage a bit as well


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[Fishstickz]

My current 2011 has 4.10s and the 5.7, on stockish size tires. For general purpose, all around use, it's hard to beat 4.10s if you have the 545RFE.

But if you have a smaller engine, and taller tires, you definitely should go 4.56. I'll predict that you'll like your truck a lot better after you regear. If it was me, I'd do gears, then tires.

I’m thinking now I might buy new wheels and tires but not install them till shortly after a regear. I cant see names on my phone but someone had a good point about the cruise RPM being way up with tall gears and tiny tires. Probably wouldn’t hurt anything as long as I took it slow but I’d rather have as little time as possible with the revs that high


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[Marley]

Once new gears are installed you'll have to take it easy anyway for awhile.....it's protocol. Lol

 

[Pull Ya]

Mileage---when did you last change the plugs? The 4.56's sure aren't going to increase your mileage but if you drive reasonably it ain't going to kill ya either. I agree with most others--4.56's are the way to go. Remember that 4.56's are going to make a little noise--no matter how good the tech is that sets them up--it's just a fact of life. Setting up gears is almost a science--make sure the person doing it has plenty of experience and knows what the hell he's doing. I'd check with Matt at Moe's Performance to see what kind of LSD he would recommend--he knows his stuff.
Jay

 

[Fishstickz]

Once new gears are installed you'll have to take it easy anyway for awhile.....it's protocol. Lol

Oh yeah thats true on the break in, im not trying to break anything within the first 500 miles lol


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[Fishstickz]

Mileage---when did you last change the plugs? The 4.56's sure aren't going to increase your mileage but if you drive reasonably it ain't going to kill ya either. I agree with most others--4.56's are the way to go. Remember that 4.56's are going to make a little noise--no matter how good the tech is that sets them up--it's just a fact of life. Setting up gears is almost a science--make sure the person doing it has plenty of experience and knows what the hell he's doing. I'd check with Matt at Moe's Performance to see what kind of LSD he would recommend--he knows his stuff.
Jay

Its been awhile on the plugs. I think it was the first thing we fixed on it after we bought it, so it was probably about 40,000 miles ago. As for the gear noise, I figure my exhaust will cover it up enough to not be too annoying. If not, guess I’d just have to get a louder exhaust lol

Both those shops have good reviews so I think I could trust either of them for a gear install—its more of the price and the brand of gears each shop uses at this point. I’ll be sure to hit up Matt cuz I’m gonna need help picking out an LSD


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[Pull Ya]

He also sells gears and the install kit, so he might be able to save you a little money on that end too.
Jay