6.4L Hemi, 4.56 gearing, stock tires

[sargenthp]

I've been looking at 4.56 gears and 37 inch tires and it would put my drive ratio slightly over stock with factory 33.3s and 4.10's.... But I don't want to lose or void my warranty as this is my first new truck and I always end up modding everything way past warranty lol

My dealer told me that I can modify as much as I want... Just if that modification breaks or something else because of the modification... warranty will not cover it.

So when I change my gears and even if I have a different shop do it... And then a ball joint goes out some time down the road... That ball joint is still going to be covered.

 

[Ratket]

I hope u had that in writing or u guys are " buddy's" in the end it is up to the dealer if they want to warranty it or not. I wish I had a dealer like that

 

[DesertCrushinPhil]

Why are you thinking of re gearing. If for towing, having done the re gear, personally, wouldn't waist the money going to the 4.10's. As for the fuel mileage, don't know where you live or elevations, but here in the Rockies, I doubt if I lost anything on mileage but the overall performance of the truck towing and for everyday driving is amazing. To my knowledge, there is not any difference in tuning between the 3.73 and 4.10??? As Ram doesn't offer 4.56 in the 2500, "if there were" would be the best you could hope for unless going to an aftermarket tune. From what all I've read, unless you want to race' I don't" there is nothing out there that would help. Also, as for exhaust and air box mods, personally would have to see the gains in black and white before I would believe it. When pulling our 13k 5'er, and the rpms I am now capable of running after the re gear, I have plenty of power without having to run into the high 4's or 5's. To put in plainly, the jump from 3.73 to 4.56 is like taking 6th gear and putting it on the bottom. that's where this 6.4 engine needs it. I love it and would do it again in a second. MY preference.

What size tires are you running? I have 37s and are considering 4.56. Right now I only tow heavy with stock tires

 

[allenmp]

I just ordered a set of nitro 4.88 for my truck they have a excellent reputation and the guy i talked to was awesome
I contacted my dealer for install and a 2 year labor warranty the install will be $1200
Plus the $1400 for the gear set with 2 year warranty
I am leveled on 35's now and the truck just won't stay in 6th gear on flat ground with 3.73 i don't think hunting for gears constantly could be good on the transmission
I was thinking about 4.56 then i read a lot of these threads and even private message a guy that went with the nitro 4.88 and was pleased with them
TheTh is a lot of knowledge and conversation on this site about this
I would encourage you to read thru a lot of them very good info on rpm and gears etc.
I am very excited to get mine done soon
I have yet to talk or see a conversation that anyone wss disappointed with it

 

[GsRAM]

I just ordered a set of nitro 4.88 for my truck they have a excellent reputation and the guy i talked to was awesome
I contacted my dealer for install and a 2 year labor warranty the install will be $1200
Plus the $1400 for the gear set with 2 year warranty
I am leveled on 35's now and the truck just won't stay in 6th gear on flat ground with 3.73 i don't think hunting for gears constantly could be good on the transmission
I was thinking about 4.56 then i read a lot of these threads and even private message a guy that went with the nitro 4.88 and was pleased with them
TheTh is a lot of knowledge and conversation on this site about this
I would encourage you to read thru a lot of them very good info on rpm and gears etc.
I am very excited to get mine done soon
I have yet to talk or see a conversation that anyone wss disappointed with it

Cool! Let us know how it goes and your impressions after all is said and done. Good luck! I'm sure it'll be awesome after it's done!

 

[loveracing1988]

I just ordered a set of nitro 4.88 for my truck they have a excellent reputation and the guy i talked to was awesome
I contacted my dealer for install and a 2 year labor warranty the install will be $1200
Plus the $1400 for the gear set with 2 year warranty
I am leveled on 35's now and the truck just won't stay in 6th gear on flat ground with 3.73 i don't think hunting for gears constantly could be good on the transmission
I was thinking about 4.56 then i read a lot of these threads and even private message a guy that went with the nitro 4.88 and was pleased with them
TheTh is a lot of knowledge and conversation on this site about this
I would encourage you to read thru a lot of them very good info on rpm and gears etc.
I am very excited to get mine done soon
I have yet to talk or see a conversation that anyone wss disappointed with it

I ran 35's for 2 years and never noticed gear hunting with 3.73's.

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[Ratket]

I ran 35's for 2 years and never noticed gear hunting with 3.73's.

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It’s all about environment, I ran 34”s with 373”s for the 4 years I had my 14,6.4,2500. 6th gear was a rare sight in the environment I lived in, truck almost never held it. I was really close to Re gearing my self. The environment I live in now is flat in comparison and low altitude so the truck did much better, but gearing was still kicking around in my mind.

 

[allenmp]

I ran 35's for 2 years and never noticed gear hunting with 3.73's.

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Me either till the last update now 6th is pretty much useless unless I'm going 80+
Which i don't do very often
I took it back twice to show then how much it shifts and they just told me it was normal

 

[loveracing1988]

Me either till the last update now 6th is pretty much useless unless I'm going 80+
Which i don't do very often
I took it back twice to show then how much it shifts and they just told me it was normal

That's weird, mine just got some sort of pcm flash that didn't seem to do anything. Definitely didn't fix the shudder issue I had.

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[allenmp]

That's weird, mine just got some sort of pcm flash that didn't seem to do anything. Definitely didn't fix the shudder issue I had.

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Yea it was the update a few months ago
I drove it 20 miles after update took it right back and complained and they did it again then said it will have to learn my driving style again. Before that i could set the cruise and it would rarely down shift. After the update it kind of stresses me lol so unless i am on a long highway trip staying above 75 i lock it in 5th
I still don't think i should have to do that i doubt it is good on the transmission either
After reading hundreds of posts i think the gear swap will help with all of it and give me some more power back
Hopefully anyways haven't seen a post we've anyone that done it was disappointed

 

[U&A]

my truck,

2016 3500SRW, 6.4 HEMI, 3.73 GEARS.

I went to 35's and 4.88's and my gas mileage went up a tad bit. re-gearing within reason, will reduce the load on the drivetrain and result a better driving truck all around. I wish I went 5.13's.

 

[U&A]

put the 68RFE in the drop down menu. the 66RFE has the same exact final drive ratios.. then all you need to do is fill in the true tire size you want to use and the gear ratio. ignore the rest. this calculator gives you LOT of ability to see what speed and RPMs will be.

http://www.grimmjeeper.com/gears.html

 

[68PowerWagon]

I ran 35's for 2 years and never noticed gear hunting with 3.73's.

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Really? I have stock tires on mine & it seems to gear hunt way more than it should. My wife is really wanting a camper & the ones she likes would be 12-13,000lbs loaded. I am considering moving from the 3.73's to 4.56 or 4.30.

 

[loveracing1988]

Really? I have stock tires on mine & it seems to gear hunt way more than it should. My wife is really wanting a camper & the ones she likes would be 12-13,000lbs loaded. I am considering moving from the 3.73's to 4.56 or 4.30.

I would be upgrading to Cummins if it were me. We just bought a fifth wheel and fully loaded we are probably 9500 pounds, plus a 1500 pound trailer behind it we got 7.9 mpg pulling it and getting up to speed takes forever and a day. Once you get there if she revs high enough you can actually gain speed going up hills, but you're talking 3rd gear going 65 mph.

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[68PowerWagon]

I would be upgrading to Cummins if it were me. We just bought a fifth wheel and fully loaded we are probably 9500 pounds, plus a 1500 pound trailer behind it we got 7.9 mpg pulling it and getting up to speed takes forever and a day. Once you get there if she revs high enough you can actually gain speed going up hills, but you're talking 3rd gear going 65 mph.

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Yeah I don't know if I could justify the $$$ for something I MIGHT only do 8-10 times a year. I ordered this truck spec'ed out to occasionally pull a 4,500lb. boat & a utility trailer with only 3-4,000lbs. in it. If I would have know I was going this route later down the road I would have at least ordered it with the 4.10's. Still kicking myself for that one.

 

[Mountaineer83]

I tow heavy with my 6.4 and 4.10s. I'd at least go 4.56 if you do a gear swap in my opinion. My 5th wheel.is around 14k and it does pretty well. Only gripe I have is the small fuel tank making me stop more often.

I cant justify a new Cummins for the few times I tow a year. Will my next one be a diesel? You bet. But right now i love my hemi and it gets me there. Maybe not as fast, but I get there all the same!

 

[2robinhood]

My 2016 3500 with the 6.4L Hemi and 4:10 gears.
With 37" X 12.50's I get about 11.5 mpg rural driving.
With the factory tires I get 9.5 mpg rural driving.
I ordered the 4:10's because from day one I knew I was lifting it.
I did the lift and tires the second day and at 40 miles.

 

[CincyCuda68]

My 2016 3500 with the 6.4L Hemi and 4:10 gears.
With 37" X 12.50's I get about 11.5 mpg rural driving.
With the factory tires I get 9.5 mpg rural driving.
I ordered the 4:10's because from day one I knew I was lifting it.
I did the lift and tires the second day and at 40 miles.View attachment 168340

If you did it again would you pick 4:10 or 4:56?

 

[2robinhood]

If you did it again would you pick 4:10 or 4:56?

I have no idea what it would be like with 4:56's.
I like the 4:10's, but don't like the 9.5 mpg with stock size rubber.

 

[CincyCuda68]

I have no idea what it would be like with 4:56's.
I like the 4:10's, but don't like the 9.5 mpg with stock size rubber.

Lol I hear ya, been struggling on which way to go. I run 35x12.5 and everything I’ve read is that I may as well go 4:56 but I’m looking for balance with power vs fuel economy.