Comparing from a 3.42 gear ratio to a 4.56 on the RAM 2500 with 37 inch tires! 

Hey there, so that size comes out to about 33.9” or a 34” tire. The 2500’s should come with the equivalent to a 31” tire if I remember correctly (265’s). I would say you are definitely ok and good to NOT have to re-gear. I ran 35’s (as do MANY people) on the 3.42 gears with no issues at all. Your truck most likely has 3.7_ in it anyway, not as “high” as a 3.42 Yes you do lose some torque being the gas hemi but for the size of the power train, 34’s won’t give you issues to the best of my knowledge and experiences with using factory gears. Most don’t re-gear until they hit 37”+ or are using the truck off-road only

Thank you for this, just went and ordered one because I can also change my TPMS 🙌🏻 I haven’t heard of this specific device before

I seem to be 5mph off from my speedometer when using GPS based app’s on the phone and occasional Radar detecting street signs. But what is odd is I was 5mph off before the swap as well. So the shop and I couldn’t really understand where speed was being taken from unless it IS at the transmission and reading driveshaft output instead 🤔

Hey there! I personally would run a 4.10 with that tire size… many run 35’s on 1500’s without any re-gearing.. I personally have a 2021 Rebel 1500 right now that came on 33’s factory and I’m now running 35’s. I think it has a 3.95:1 in there but I’d have to double check. I think if you towed a lot and didn’t mind losing the “high end” speed then sure, 4.56 would be fine. As well as for some decent offroad-ing. But for a 50/50 driving habit and just driving it mainly as a daily and just normal day to day truck activities, I don’t think you can go wrong with the 4.10’s and 35’s (Edit: had to change the semicolons to periods in the gear ratios so it wouldn’t “timestamp” the video)

@@DevonsGarage thanks 😊

Every 68rfe has flare between shifts it’s how the transmission was designed.

@@YippeeKyyay really? Interesting

Hey man! Couple of things, 1, that is pretty cool that it’s going well with the 3.42’s... I have not heard good things with the amount of stress later down the line at like 75k miles etc. I really wanted to keep those gears for highway but this was a better option for all around and 90% of people I talked to agreed for the power trains sake. 2, my speedometer to GPS difference for some reason stayed the exact same before and after the gear installation.. something the shop and I have also been slightly confused. I have an actual speed app which I used and then also Waze but both said 5 mph difference. 3, yes the 75/80mph is where the con comes to play with 4:56’s (same with RPM, I get pretty high up there at these speeds) and it was the most hesitant part for me as I drive highway quite often. All in all , I would say that at the end of the day 4:56 is definitely easier on the truck no doubt and that 3:42’s can indeed be used as guys are doing it. For that, I would ask other questions to myself if I was considering the swap like towing, how much highway use compared to city, what speeds I plan to drive most of the time, am I planning a tune, etc etc. Speaking of tune, I just got my 5” piping and tuner in to do some “modding” but can’t make a video on that around here 😅 if you know what I mean haha

@@DevonsGarage My truck isn’t a work truck, but I have pulled a dump trailer with gravel for the driveway, about 14,000 pounds. I held it back in 5th, and it did amazing, I was actually surprised. I’m keeping this one on the 30hp tow tune, and with the better transmission programming, I doubt the transmission will ever be an issue. I do plan on a valve body from revmax when I service the transmission for the first time, but that’ll be a few years down the road. I’m guessing your speedometer gets it’s information from the wheel sensors, that’s strange.

@@fearlesscamshaftleader2197 lol I have the SAME set up as you, but I have a revmax valve body, and 35K on the odometer. I have some shift flare between 4th and 5th, but nothing crazy. Other than that my truck gets 14.9 combined...it's great.

4.56 gears for power 4.10 gears for better gas mileage

They offer a 4.44 in the factory AAM gears

456

4.88

Oh man that’s a gnarly tire! Heck yeah! Shoot, honestly me personally (being that it is also a 1500 and I wouldn’t want my transmission to handle too much starting torque from every stop) I would go 4.56 minimum… however your freeway speed will be pretty limited hence why the shop is probably recommending 4.10’s… You will have to ask yourself if you want more of the better gas mileage (if that’s even a thing with 40’s lol) and top speed to get the 4.10’s (also if you plan to be at higher speeds quite often like above 70-75 as your usual drive) OR have a lighter “load” on your drivetrain, more low end torque, but slower high up then the 4.56 or above. Both are great gears Think of a battery drill where you can change the speeds on top between 1 and 2… speed 2 is fast but stops at a bind (no torque) while speed 1 has all the torque to get through tough material using larger drill bits

@@DevonsGarage it has a 4l80 trans just rebuild it. The previous owner put 5.38 yukon gears. What are your thoughts on those? It's more of a mud & weekend truck.

@@christianmoreno5424 Now that sounds more in the range of what I’m used to hearing for 40’s (especially in the Jeep world). 5’s are great for off-roading (probably could even light those 40’s up if the driveshaft doesn’t bind first lol jk) It’s all about compromise, I was VERY in between 4.10’s and 4.56’s with the Ram but after talking with the shop that had done a ton of the same truck with tire combo, I went with their recommended 4.56 to have more low end torque and less stress on the drivetrain. The higher the number, the less stress but it all comes with a cost: Engine speed and Practicality I would see if you could find anyone running that size tire on your same truck and see what they are running (if there’s any info out there) to kind of get some specific feedback. You could even see what people are gearing to with 37” tires and how they like that setup. Because if they are 4.56 with 37’s and they are saying it’s a perfect “like factory” match, you will most likely have some unwanted stress with the 40” tires I haven’t done much research for what should be ran on 1500’s past a 37” tire since I usually cut the limit on 1/2 ton trucks at 35” tires for longevity. The 3/4 tons however (2500’s) I would say 40’s all day! Haha But yeah, see if you can find anything around!

?? At least 4:88 or so . Probably more . Thats a big hoop..

I hope to get to that level, need to get a backlash gauge and start practicing

It didn’t change as much as I thought it would. But that’s probably due to all the emissions stuff on this truck. I’m getting an average of 13 without towing. Stock with 35’s I was able to pull about 17 without towing. I think the higher RPM’s plus the tire size of course is what is mainly killing the MPG after the gear swap

Best place near the Antelope Valley (where I am as well) is definitely Offroad Bully at least in my opinion from personality/price/overall experience. Otherwise another decent shop out in Sylmar area is Jet Rear end (pretty sure that’s the name, it’s been a while). Gears themselves were around $1100 and labor for mine was around $800. $1900 was a really good price for me. And the job was done extremely fast!

@@DevonsGarage $1900 for both axles?? That’s amazing. I paid that for one lol.

(45hp tune, 3 inch lift)

You shouldn't have any problems with it. You may notice a decrease in fuel mileage and a little more lug under a load. But it won't hurt the truck.

@@codygalloway5386 thanks

Lower mpg for sure

I know it was 4.56’s as I got the boxes that they came in (well I guess there is still a possibility the gear company could of messed up) but I’d say it was 4.56’s.. I’ve seen similar RPM’s with that size tire and setup, but there always could be that chance without actually going in there and counting the teeth or seeing a stamped part number

@@DevonsGarage according to a gear calculator, with a 36.5 (37) inch tire, at 75mph your rpm’s would be 1951 for 4.56 and 2088 with 4.88s, in 6th gear. I just saw 75mph and 2100ish rpm on your dash and thought maybe you had gotten 4.88s. Ian putting 4.88s in mine soon is why I was asking. I tow with mine so going with 4.88s

@@kylemoore9626 oh! Ok one thing I will say is the speedo was off about 5 mph, so I was actually going about 80mph and according to google, those 37’s specifically are 36.8 (not sure if that all makes a difference in the math). Off-road Bully highly recommended that I did 4.56 for highway speeds. To me it felt good and didn’t get too high on the RPM’s at 80. I always remembered being about 2000-2200 at around true 80 mph but it’s also been a little while

Dana 60 equivalent made by AAM

I wouldn’t recommend that high of a gear for that size, that would cause your 80mph to be near 3k rpm

4:11

I say it awkwardly in the video when comparing to the gearing of the truck as the other commenter had pointed out and I realized. But, how you are saying I haven’t personally experienced, the larger rear gear allows more top speed but you have to put in more effort to start out or while going up hill. Then when on the smallest gear in the rear, you can pedal very easily and fast but you barely move anywhere. This makes it easy to go up hill. This is how I at least remember it and the other commenter agreed. I apologize though if I am wrong, just trying to give some analogies, I probably should of done the explanation with an actual bike

DevonsGarage Get on a bike and check your theory. Think of a dirt bike. When you want more torque (easier to accelerate and go uphill) at the wheel you go to a larger rear sprocket. When you want to go faster (slower to accelerate but higher top end speed) you put on a smaller sprocket. Same for a bike. Not putting you down but if you have a “good amount of knowledge” on the subject but don’t understand the basic concept of gear ratios it makes me wonder...

DevonsGarage When you changed the hearing on your truck to accelerate quicker but you lost a little top speed ask the guys if the pinion gear (front sprocket) got bigger or smaller compared to the ring gear (rear sprocket). They will be able to help you.

SoCali7three I believe this may be like the other commenter had stated I worded things wrong in the video. On a bike, a 1:1 is easy to start off.. same teeth pedal and rear wheel (let’s say 35 to 35) sprocket. While then the less teeth on that rear sprocket (lets say 11 teeth, so 35 pedal, 11 rear) will create more speed on the rear wheel but harder to start. We are in agreement on that. Now in the truck and why this becomes a harder analogy, a 3.42 gearing is faster top end than a 4.56. The driveshaft spins 3.42 times around to 1 full axle rotation, therefore less engine rpm speed compared to vehicle speed. With the 4.56, I am getting a full rotation more on the driveshaft to complete my one wheel rotation. So more RPM speed versus vehicle speed. Which is why I lose the top speed and cruise around 75 at 2k rpm instead of my original 1500 rpm. I agree with you just the bike situation throws things off because it sort of explains backwards. We are adding teeth to the rear to get our ratio, not taking away. More teeth than driving gear, easier. Less teeth than driving gear, harder.

DevonsGarage This comment makes some sense now. Your last comment: Larger rear gear on bike means faster too spread, smaller rear gear easier to pedal but less speed is completely backwards from reality. All good, not worth more banter. Jump on a bike sometime and let me know if a larger rear sprocket gives you more top speed vs. a smaller rear sprocket...I think you’ll find that theory is backwards.

That is crazy, I believe it. My build sheet for the truck when I bought it new said 3.73 but then further down the sheet it said “sport package” with a sub menu and in there it stated 3.42 which really bummed me out. But it has definitely been awesome now with the 4.56 👍🏻

@@DevonsGarage I know it may say things on paper but I can assure you 2013-2018 99% of the diesel 2500/3500 are only 3.42s I researched forever to find 4.10s when I bought my 2016 couldn't find jack other than 3.42s and finally realized that's all you could get so I finally bit the bullet and bought the exact truck I wanted and didn't worry about gearing because I knew I would change that anyway

Max Penetration oh wow see this part I didn’t know, but I agree I did the same thing because I wanted everything else in the truck and knew I would have to regear anyway once I put on the 37’s. Really sucks that they are putting them out like that. I guess for more MPG or something lol

@@DevonsGarage 2500/3500’s come with 3.73’s with the gas hemi engines, once you add the Cummins option it changes to 3.42, doesn’t matter what trim package

@@DODGEramDAMN according to my build sheet, it states 3.73 gearing right after the 6.7L Cummins then off to the right it says Sport package and has a sub menu under it where it listed the 3.42 gears. Which is the only reason I mention it that way. When I asked the service department why they rip out the 3.73’s, they said because the sport was looked at as a more highway commuting vehicle idk 🤷🏻‍♂️ but a lot of guys have the 3.73’s with the diesel stock

Lol nah man, I’ve gone through a lot of cars to get my truck. I work for everything I do, been a maintenance tech for 7 years. I’d rather enjoy my vehicles and traveling than buying a house 🤷🏻‍♂️

@@DevonsGarage sounds like you got your priorities in order. nice truck though

lifted 98 I don’t like being grounded to one place plus I have no kids, no wife, etc. I live for the outdoors and adventures. Honestly a house is just debt to me, the vehicles are a hobby. But to each their own, I don’t mooch off anyone I actually help those where I stay by giving them extra money and any help they may need. Living in some sketchy apartment in SoCal for $1300 a month (yes that is the pricing) is just not where I would be happy. I appreciate the comment about the truck though! Don’t think this reply is personal, it just gets brought up occasionally so I feel as though I have to explain why I would personally rather rent and buy smaller stuff like cars than just a house and drive around a civic. Life’s short 🤷🏻‍♂️ gotta enjoy how you live

@@DevonsGarage man I wish I could have lived with my parents a little longer looking back on it! Moved out at 18 and you’re right! Renting an apartment in the city for more than it’s worth is a drag! And financial set back. Now I’m dying to buy a house because the mortgage will be less than rent and at least I won’t be throwing my money away. People hating but I promise you it’s only because they wish they got along well enough with family to stay. Its cheaper/more beneficial for everyone really! Do you man! Sweet truck 😎

@@Thedriver96207 appreciate this so much! 🤘🏻 It’s definitely the truth!! 😎

Oh yes I definitely agree, but there isn’t much on the market or recommended to have to upgrade for 37’s on a 3/4 ton truck with solid front and rear axles (Dana 60 up front and I believe but may be wrong, a Dana 70 rear). Now will it wear faster than the factory 31’s on that same truck? Heck to the yes! Lol But comparing that to putting 37’s on a 1/2 truck like a 1500 or F150, and that’s where you REALLY tear apart bearings, suspension components, and all steering components. Usually, at least from what I’ve read, the weakest spot in going 37’s in a 3/4 ton is the need to re-gear. 1/2 tons require a lot of upgrades to do it correctly (if that is even a thing: ‘correctly’)

They don't really make a bigger axle though. If you wanna drive with 110's on a ram, you'd be the only one..

Now that would really add some low end power! I stayed around 4.56 mainly for the highway RPM’s. I drive up north in CA a couple times a year and usual traffic is around 80mph on the 70mph posted, I didn’t want to be too much higher than a constant 2k rpm’s

Derek Crismond, I apologize if I over-explained, the gearing does work just like a mountain bike for those that aren’t familiar with the actual gears inside the truck. The ratio still relates to the turns of the driveshaft. 3.42, a low gear and 4.56 a high gear. 3.42 have less teeth and allow more speed vs torque. The 4.56 would of course be opposite, more teeth and easier for torque but less speed. We are both in agreement, I just tried to explain in analogies for others to also understand. I’ll try to be simpler in the future 🙌🏻

@@DevonsGarage I figured you knew you what you were talking about. However, you say it completely backwards in the video when using the bicycle analogy. No biggie, just hatin' lol.

@@AFPECE You are right, I just re-watched the video.. I shouldn't of mentioned the bigger and smaller sizing because it does not relate to the same comparison with the gears. The theory does, but I went backwards on high/low gearing vs bigger/smaller sizing. I'm glad you pointed that out honestly because I don't think about those things sometimes lol and have to rewatch myself to see it differently. I appreciate you man and I definitely try to learn from my mistakes, that's what makes the car community awesome, we learn from each other!

Are you saying that if i were to do 4.56 gears in my 6.7 dodge that i would loose towing capability ? And maybe fucking my drive train if i tow a trailer ? Please reply to this when you get achance

Oh no not that, ABIDING speed limits. That came out as a horrible mashup 😅

The idea behind gearing is simple, we put in higher or lower gears to relieve stress on the drivetrain whether it is for larger tires, towing, or for some it is strictly performance based. I took the easiest differences to show on camera with the before and after. Load does go down. Speed IS affected with RPMs. In my case, I lose top end. I tried to be very thorough on explaining why the differences occur. I have a very good understanding the mechanical side to how this works and only didn’t perform the work myself because I do not have a tool to measure backlash to be able to shim correctly. In this video, I was honestly just trying to show the immediate differences and explain why I went with the gears that I did. I am not here to persuade someone with wrong information. I apologize if the video was upsetting as that was never my goal. I used the tools I have to compare the differences that I could show with the 3.42 vs 4.56

@@matthewloew2309 surprisingly no, I had the opposite happen because of my low end torque with the 4.56. At least this is in regards of the gearing for my tire size. Now if you want to say my fuel economy went down because of 37’s, sure, that is expected. And if you are comparing highway speed only, also sure. But overall average I was not putting that stress on the drivetrain trying to get up to speed and saw minimal difference on mpg before and after but was able to get a better number during city driving comparisons when just comparing gear ratios.

👍🏻

Incorrect, I have the build sheet from buying it brand new. Window sticker legit states 3.42 gears both front and rear 👍🏻

@@DevonsGarage Yeah I was looking it up just now and Chrysler put 3.42s in their 2500 and 3500 trucks sense 2013. It was the only gear available in the Short box trucks.

@@DevonsGarage I don’t know what I was incorrect about but ok. Dodge has all ways put 3.55, 3.73 and 4.10 gears in their heavy duty truck until 2013 and it appears to have stoped in 2019. Now they are back to the way it was. It didn’t last long. I been driving Dodge trucks sense the 80s. That was the only gear ratios available. 3.73 gears were still available in your year model truck but you had to get the Crew Cab long bed it seams.

@@stgraves260 uhm, before you edited your original comment, you wrote that dodge does not put 3.42 gears in their trucks. I said that is incorrect as I have the build sheet/window sticker for my 2018 RAM 2500 that 100% states it came with 3.42’s from the factory. That is what you were incorrect about

@@DevonsGarage The message should not have sent because I wasn’t finished yet. My phone froze up and would not let me finish.