Gears For 37s?

[ricky_bobby]

Thanks for the opinions.

I will most likely go with 4:10s.

Also, in no hurry, because im not pulling anything at the moment and do most daily driving.

I wanted to get it closer to stock gearing because my Trans goes into high gear around 45 mph.

I don't know if my Trans tuning has to do with this or not, though.

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4.10 AAM gears sound the best bet for you, the best of both worlds.

I have the same problem, the trans is always hunting for a higher gear, but if you regear, it won't be 'lugging' when it upshifts; for example, when you go into 6th at 45mph now, it's probably 250rpm lower than if you had 4.10 gears - look up the rpm chart and I'm on 35's.

It bothers me, and I can only imagine 37's / 38's.

My biggest complaint with the 3.42 gears and auto is the constant upshifting into 6th below 50mph; it drives me insane, I don't tow a thing, and I want to regear just to offset that; I have to run in Tow/Haul all the time to feel like the truck isn't lugging.

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[jetursi]

4.10 AAM gears sound the best bet for you, the best of both worlds.

I have the same problem, the trans is always hunting for a higher gear, but if you regear, it won't be 'lugging' when it upshifts; for example, when you go into 6th at 45mph now, it's probably 250rpm lower than if you had 4.10 gears - look up the rpm chart and I'm on 35's.

It bothers me, and I can only imagine 37's / 38's.

My biggest complaint with the 3.42 gears and auto is the constant upshifting into 6th below 50mph; it drives me insane, I don't tow a thing, and I want to regear just to offset that; I have to run in Tow/Haul all the time to feel like the truck isn't lugging.

I got a new boat and have been towing it around sense my original post. It's about 7k with trailer and I'm only averaging 8mpg on flat highway. I switched tuning from stock to 120hp and no difference at all. I do notice the 90hp tune feels the best especially if I use manual shift when going up and down grades otherwise the damn thing it trying to get into 6th gear going 60mph up hill with a load.

Does anyone know of AAM makes Mopars gears. A friend told me he paid under 800$ for both front and rear gear sets from his dealer. Seems way to cheap.

Also did you do both carrier and pinion bearings as well?

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[ricky_bobby]

I got a new boat and have been towing it around sense my original post. It's about 7k with trailer and I'm only averaging 8mpg on flat highway. I switched tuning from stock to 120hp and no difference at all. I do notice the 90hp tune feels the best especially if I use manual shift when going up and down grades otherwise the damn thing it trying to get into 6th gear going 60mph up hill with a load.

Does anyone know of AAM makes Mopars gears. A friend told me he paid under 800$ for both front and rear gear sets from his dealer. Seems way to cheap.

Also did you do both carrier and pinion bearings as well?

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Surprising because I thought the 2019+ trucks had 3.73 gears from the factory ? Which should be an improvement over the 3.42's I have on my 2018. That being said, if you are on 37-38" tires, 3.73's aren't necessarily ideal and probably put you in the rpm spread that I get on 35's with 3.42's.

Like I said what I end up doing is Tow/Haul all the time to get around it, it keeps it in 4th until about 55mph and 5th until 65mph - its the best I can do - but off the line I'm sure it would feel 'sluggish' with the gearing regardless of what mode I'm in

AAM are the gears that are installed in our diffs from the factory - If you are going from 3.73 to 4.10 its about an 11% gearing increase. Its more substantial if you have 3.42 in my case to jump to 4.10

The Ring & Pinion sets, your friend is right, are probably about $800 in parts - however there are bearings and seals that you could replace as well - either way you slice it, its the labor that is going to cut you - its going to be about 8hours easy per axle

East Coast Gear Supply in Louisburg NC not too far from my house, gave me a quote of about $3200 with tax, installed - they replace all wear items, bearings, seals, etc in the differentials while they are swapping the ring&pinions out, and that did include gaskets and fluid

Of my price quote, R&P's were about $800, about another $500 in install kits, gaskets etc, and then about $1600 in labor - its not a quick job.

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[trick76cj5]

Please keep us updated on your updated fuel mileage - you have a lot bigger/heavier tire than I would ever go with so if you keep similar fuel economy after regearing to 4.10's I'll be impressed and definitely put gearing on my things to do list - these 3.42's just feel lazy I feel like the truck should have more low end grunt than it does.

I’m getting 15-17mpg on the highway depending on traffic … I’m running 80mph avg.


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[ricky_bobby]

I’m getting 15-17mpg on the highway depending on traffic … I’m running 80mph avg.

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Thats not bad at all considering 37's - I am on 35's (34.6" to be exact) and stock wheels, just a 30hp tune, my last tank I averaged 19mpg and this tank I averaged 18mpg - my highway speeds are 70-75ish - I notice when I get to 75 or above due to the higher rpm the truck runs smoother.

How was the 4.10's on 35's? You said it was about all the most gear you wanted to run - was the 4.10 on 35's overkill? You run unloaded most of the time same as me - I'm not a fan of the 3.42 gears on this truck but don't want to 'overkill' it either so 3.73 always was the logical choice.

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[trick76cj5]

Thats not bad at all considering 37's - I am on 35's (34.6" to be exact) and stock wheels, just a 30hp tune, my last tank I averaged 19mpg and this tank I averaged 18mpg - my highway speeds are 70-75ish - I notice when I get to 75 or above due to the higher rpm the truck runs smoother.

How was the 4.10's on 35's? You said it was about all the most gear you wanted to run - was the 4.10 on 35's overkill? You run unloaded most of the time same as me - I'm not a fan of the 3.42 gears on this truck but don't want to 'overkill' it either so 3.73 always was the logical choice.

At 70-75mph the 35’s and 4.10’s were good and I figured that would be a great combo in other parts of the country where you can’t go over that speed for risk of a ticket. The around town driving was more fun too.

Also, the more gear you can run, the less load you place on the transmission. Honestly, not a terrible concern for many, but that is another benefit.

I don’t think you will regret either the 3.73 or 4.10.


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[ricky_bobby]

I agree - the only pill hard to swallow is the 3k cost to swap - but at this point I need to regain something back - even after running 30hp tune I probably need to hyper mile to get over 20mpg again, my last two tanks were 2/3 highway and 1/3 city and netted 18 and 19mpg hand calculated, its not bad but you guys are on much heavier 37" tires

I know that mpg drops off decently after 70mph but with more gearing, whether 3.73 or 4.10, you have more mechanical torque pushing the truck down the road and needing less throttle input to maintain the same speed so in theory if you are at an ideal speed/rpm, you could be getting better economy -

I.E. at 70mph right now for me I'm just under 1500rpm, yes the rpm is lower but I feel like I need more throttle input to maintain that speed since the rpm is lower. Adding 130rpm with 3.73's and 250ish rpm's with 4.10's allows more rpm and more power at a given speed I guess, if I understand gearing physics right.

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[jetursi]

Surprising because I thought the 2019+ trucks had 3.73 gears from the factory ? Which should be an improvement over the 3.42's I have on my 2018. That being said, if you are on 37-38" tires, 3.73's aren't necessarily ideal and probably put you in the rpm spread that I get on 35's with 3.42's.

Like I said what I end up doing is Tow/Haul all the time to get around it, it keeps it in 4th until about 55mph and 5th until 65mph - its the best I can do - but off the line I'm sure it would feel 'sluggish' with the gearing regardless of what mode I'm in

AAM are the gears that are installed in our diffs from the factory - If you are going from 3.73 to 4.10 its about an 11% gearing increase. Its more substantial if you have 3.42 in my case to jump to 4.10

The Ring & Pinion sets, your friend is right, are probably about $800 in parts - however there are bearings and seals that you could replace as well - either way you slice it, its the labor that is going to cut you - its going to be about 8hours easy per axle

East Coast Gear Supply in Louisburg NC not too far from my house, gave me a quote of about $3200 with tax, installed - they replace all wear items, bearings, seals, etc in the differentials while they are swapping the ring&pinions out, and that did include gaskets and fluid

Of my price quote, R&P's were about $800, about another $500 in install kits, gaskets etc, and then about $1600 in labor - its not a quick job.

Thanks for the info, so me going from 3.73 to 4..10s isn't goes to change much, part of me thinks 4.56s would be to much for my applications, would the 4.47s put me in the stock gear spead with whatever the stocks tires are. 31"s I think

I was going to do the gears myself, I've setup a few sets of gears before so I'm not concerned, just need to take my time and go slow.

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[Chrisn162001]

Thanks for the info, so me going from 3.73 to 4..10s isn't goes to change much, part of me thinks 4.56s would be to much for my applications, would the 4.47s put me in the stock gear spead with whatever the stocks tires are. 31"s I think

I was going to do the gears myself, I've setup a few sets of gears before so I'm not concerned, just need to take my time and go slow.

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I have 4.56 with 37s if I had to do it over again I’d go with 4.30s.

I do a lot of hwy driving over 80mph though.


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[jetursi]

I have 4.56 with 37s if I had to do it over again I’d go with 4.30s.

I do a lot of hwy driving over 80mph though.


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Do you have 48RFE or aisin? I forgot about 4.30s. Also I'm debating on 38s depending on prices when I need tires within next year.

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