New tranny already.. need to regear for 37’s.

[Steven Barnes]

2018 Pw, 63 k miles, 40 k on 37’s.

95% daily driver. New transmission installed. Glad I got the Lifetime warranty.

I am learning that regearing will get more life out of the transmission.

What ratio should I go to? I’m going to keep running 37’s.

 

[Odin]

I'm planning on doing 5.13s with my 37s when my warranty is up.

Sent from my SM-G986U using Tapatalk

 

[olyelr]

5:13’s

Did you have any issues with the dealer warrantying the trans when you have 37’s on there?

 

[Mallcrwlr3000]

Best thing I have learned is when parking on any incline, put in neutral and engage the parking brake, then let the truck relax and put it in park afterwards. My driveway is a pretty decent incline and i got 206k on another truck with no issues yet.

 

[BowerPower]

I'd recommend doing the math to get you back as close to stock as you can. What is the animal gear ratio that puts it back as if you still has 33s and 4.10. Later tonight when I get a break I'll find the formula and update you if someone doesn't beat me to it.

My two cents, you're driving a truck with a powertrain designed for hailing over 14,000 pounds in max tow configurations. I would find it hard to believe you killed your transmission so quickly with 4 inch bigger tires. That truck comes in stock forms with less than 4.10 gearing which is what the 37s effectively did.

I will also add, dodge is not known for good transmissions (exception, 727). Why I'm glad they switched to a German company (ZF) that specializes in transmissions.

Sent from my SM-N975U using Tapatalk

 

[Steven Barnes]

I did not have any issues getting the warranty to cover the replacement. It took about a week from the time I drop it off for Chrysler to approve it. And then another week for them to find a transmission. The specific transmission was on back order. The dealership got the transmission on a Friday and I drove away the following Wednesday. Cost me $100 deductible. Couldn’t be happier.

 

[Steven Barnes]

37 compared to 33‘s or about 20% larger. So I imagine I’ve got a gear down about 20%.

is this sound thinking. So 20% lower gear than 410s

410x 20%=82
410 + 82 = 492
so 488 or the next numerically higher option should get me close to factory,

next question.. what vendor is most reputable and makes ring n pinion gears for my truck?

 

[Steven Barnes]

Thanks for your input.

 

[RoadRamblerNJ]

5.13's
You won't regret it.
My 2500 just went out of warranty and when I need tires, the rears are getting done.

Sent from my SM-N910V using Tapatalk

 

[BowerPower]

I have the math!
Formula: (gear ratio)÷(tire size) = (gear ratio)÷(tire size) solve for unknown gear ratio

(4.10)/(33)x(37)=4.596

The actual ratio will depend on what manufacturers make. A higher number will be great for around town driving and off road for the extra torque but will kill mpg at highway speeds.

I have not driven an 6 speed PW with 33s vs 37s so I don't know how if feels to dive. That is barely enough of a difference for the truck to care. All you have done is lower your effective gear ratio 3.66 on 33s. The other stock gear ratio for ram is 3.73. There is no way that 37s did your transmission in.

You need to do what you think is right and will give you peace of mind. At the end of the day, that is all that matters.

Sent from my SM-N975U using Tapatalk

 

[olyelr]

I have the math!
Formula: (gear ratio)÷(tire size) = (gear ratio)÷(tire size) solve for unknown gear ratio

(4.10)/(33)x(37)=4.596

The actual ratio will depend on what manufacturers make. A higher number will be great for around town driving and off road for the extra torque but will kill mpg at highway speeds.

I have not driven an 6 speed PW with 33s vs 37s so I don't know how if feels to dive. That is barely enough of a difference for the truck to care. All you have done is lower your effective gear ratio 3.66 on 33s. The other stock gear ratio for ram is 3.73. There is no way that 37s did your transmission in.

You need to do what you think is right and will give you peace of mind. At the end of the day, that is all that matters.

Sent from my SM-N975U using Tapatalk

In my opinion the factory 4.10s with 33’s is a joke. Feels like it should be 4.56’s at minimum, if not 4.88’s, with the stock tires. The 6 speed gearing is completely ridiculous (not to mention the electronics of it is a joke too). I dont understand why they have it geared so you are going nearly 50mph before it shifts out of 2nd gear...yet when you slow down and take off again it wont hardly drop lower than third unless you hammer on it.

The trans in my truck is the only complaint i have about it. If i dont trade this one up for an 8 speed, then i will be swapping to 5.13’s (even for the 35’s i am currently running).

 

[2003F350]

In my opinion the factory 4.10s with 33’s is a joke. Feels like it should be 4.56’s at minimum, if not 4.88’s, with the stock tires. The 6 speed gearing is completely ridiculous (not to mention the electronics of it is a joke too). I dont understand why they have it geared so you are going nearly 50mph before it shifts out of 2nd gear...yet when you slow down and take off again it wont hardly drop lower than third unless you hammer on it.

The trans in my truck is the only complaint i have about it. If i dont trade this one up for an 8 speed, then i will be swapping to 5.13’s (even for the 35’s i am currently running).

Sounds like you accelerate hard all the time. At 50 mph I'm already in 4th gear on my '17. And it's bone stock.

 

[crazy jerry]

37 compared to 33‘s or about 20% larger. So I imagine I’ve got a gear down about 20%.

is this sound thinking. So 20% lower gear than 410s

410x 20%=82
410 + 82 = 492
so 488 or the next numerically higher option should get me close to factory,

next question.. what vendor is most reputable and makes ring n pinion gears for my truck?

thats the common thinking however people fail to realize youll have heavier larger diam tire. may want to read this https://www.khanacademy.org/science...tia is a property,to mass in linear mechanics.

 

[62Blazer]

33" vs. 37" tires are around a 12% difference in circumference (or how far the truck will move with each rotation of the tire). As stated above on paper a 4.59 is the gearing number to make up for ONLY that difference, and obviously 4.56 is the closest that is available. However, and already stated, it does not make up for the increase weight and rolling resistance of the larger tires....and the simple fact it's very hard to tell the difference between something like 4.10 vs. 4.56 in real life. I would recommend at least 4.88 or even 5.13.

But also as said above, I don't think that 37" tires was the biggest issue with the trans only lasting 63k miles. You are talking about the same powertrain setup used on trucks with 3.73 gears and rated to tow upwards of 14k lbs. which put a lot more stress on it than 37's. I do think a big part of it is recalibrating the ECU for the tires though.

 

[22hemi13]

I’m a firm believer in manually selecting your gears too. My truck NEVER sees anything more than 4th gear. 150k miles. I’ve ran 35,37,39 and now 40s all on stock gearing. Yeah it’s not great and gears are in the mail. But……. I stop my truck from shifting a thousand and times and gear hunting. And I kinda beat the crap out of my truck too. Drive to cali, Moab and all over Arizona for wheeling. Not a pw but the drivetrains all the same minus the lockers and stuff. So I may be crazy but I don’t think the trannys just blow up cause of bigger tires.

 

[SeppW]

37 compared to 33‘s or about 20% larger. So I imagine I’ve got a gear down about 20%.

is this sound thinking. So 20% lower gear than 410s

410x 20%=82
410 + 82 = 492
so 488 or the next numerically higher option should get me close to factory,

next question.. what vendor is most reputable and makes ring n pinion gears for my truck?

Can't go wrong with Yukon or the OE, AAM (may not have the ratio though). Need to do front too. Easy to FU and if you're if not comfortable doing it, need to find a reputable axle shop that can do it right. If it's not right than you'll have to do all over again, assuming the R&P isn't destroyed. Yukon has an excellent master install kit. Figure $2500-3000K parts and labor if farmed out, conservatively.

 

[olyelr]

Sounds like you accelerate hard all the time. At 50 mph I'm already in 4th gear on my '17. And it's bone stock.

I will admit, that is certainly in acceleration mode. And its with 35’s. But even so...why? Thats just geared too high IMO. Im just spoiled with the 8 speed in my half ton work truck...its almost flawless.

 

[John Chappell]

Gears are, effectively, levers (including the tires themselves). Collectively, the math proffered up here accounts for some of that. What it does not account for is rotating mass, acceleration and various forms of friction.

Also, I’ve had a half dozen Jeeps, at some point you have to wonder how well the ring and pinion will hold up as the area of contact between the individual teeth decreases. This would make more sense if you had them in your hands, it makes them less durable. Less “meat” between them.

 

[crazy jerry]

Also, I’ve had a half dozen Jeeps, at some point you have to wonder how well the ring and pinion will hold up as the area of contact between the individual teeth decreases. This would make more sense if you had them in your hands, it makes them less durable. Less “meat” between them.

examining the two gear sets in question would tell the story but i dont think i could agree with what youve said.
as the numeric ratio goes up, the pinion head diameter gets smaller. if im not mistaken they typically lower the tooth count on the pinion to maintain the same or very similar tooth profile and strength to that of a lower numeric ratio. so your losing none or very little contact patch between gear faces.
there is one thing to mention with higher numeric ratio gear sets. as the pinion tooth count goes down, you will end up with less teeth in contact with the ring teeth at any given time, versus a lower ratio higher tooth count pinion.
some people have made the argument that the lower numeric ratio, higher tooth count pinion gearset is a stronger setup. how ever , the massive size of any ratio gearset for these axles is far stronger than what we need ,unless you were doing something stupid like professionally sled pulling with a hopped up deisel putting out big torq.
as for wearing out the gears, that wont happen any time soon

 

[56PW17]

If it was a manual trans there would be no comments hahaha