4.56 or 4.88 gears for towing with 6.4 Hemi?

[SouthTexan]

(Axle Ratio x Vehicle Speed x Transmission Ratio x 336.13) / Tire Diameter in inches = RPM

(5.13 x 75 mph x .625 x 336.13) / 34 inch tire = 2,377 rpm

 

[Snacktime]

I would spend the money on 5.13 gears to help take as much stress off the transmission as possible. Only time you should avoid to much gearing is if you don't have overdrive!

 

[MetalGrand]

I got a quote this morning from a local shop for 4.88 Yukon gears for $1550 out the door. I’m thinking that’s a pretty nice deal and I think I will pull the trigger.

 

[Bldrinker]

I got a quote this morning from a local shop for 4.88 Yukon gears for $1550 out the door. I’m thinking that’s a pretty nice deal and I think I will pull the trigger.

thats way cheap. I paid 2300.
My Yukon gears whine at 65-70. Not sure it’s the gears fault or not. Might be the setup.

 

[MetalGrand]

thats way cheap. I paid 2300.
My Yukon gears whine at 65-70. Not sure it’s the gears fault or not. Might be the setup.

How loud is the whine?

 

[dhay13]

Steeper gears are going to be noisier. A higher ratio has thicker 'cogs' with more angle on each 'tooth' so makes more noise. With tire noise you probably won't notice it anyway.

 

[GsRAM]

With 35" tires I'd do a 4.88 gear.

Stock size 4.56s.

Both will be a huge improvement over the 3.73s. As suggested, with what your asking from the 6.4, 5.13s may not be a bad idea. 12k is a heavy rig.

That's probably close to double what my tt weighs. My truck pulls my rig wonderfully and I know I could go another 2k in loaded trailer weight no problem. But 6k more, to me your in diesel territory, so I can see why your looking to regear.

As an aside, I've recently had a conversation with another member that leads me to believe that the rear axle in 2500 starting in 2018 or 2019 may not be the same as 3500 srw.

Check your driver's door sticker. My truck, produced in 12/16 has a 6500 GRAWR. So that should be the same as 3500 srw.

If your GRAWR is 6000 you may have a different (lighter duty) rear axle. I haven't confirmed that yet however. Something to think about though as I believed that after the 2014 hd update, the only difference between 2500 and 3500 are was the rear springs. But that may not be the case.

 

[tron67j]

Why does EVERY thread turn into a payload debate??????? We're talking gears here!!!! Stupid 2500/3500 argument has been beaten to death on this forum and EVERY other net forum. Go find a relevant thread to hash it out PLEASE!!!!!!

OP, I'd say it all comes down to what kind of driving you do. With your highway driving at 75 I'd probably go 4.56 with stock tires or 4.88 with slight up-size. I tow the exact 5th wheel with 3.73 and stock tires and have read these forums extensively. If/when I do the re-gear I'd probably go 4.56. That's a huge change from the stock 3.73. 4.88? Sure, that would be fine as well. I think it would be difficult to even tell the difference between the two.

The best tool I've found is an RPM calculator and playing around with my truck to replicate the RPMs at cruising speed so I know what I'd be in for.

Because gears are only one part of the towing equation. Just trying to help by providing an alternative line of thought so that everything is considered when someone is about to spend money. Name calling doesn't contribute to the the OP's gathering of information, they asked and everyone can weigh in with data, then the OP makes their decision. But to your original point, I can put even more gears on a bike but it won't matter if a 1,000 pound person jumps on to ride.

 

[mtofell]

Name calling doesn't contribute to the the OP's gathering of information,

Name calling? The word "stupid" was used to describe an argument.... not a person.

 

[AFMoulton]

Doesn’t change the fact that payload matters.


2018 Ram 2500 6.4L 4x4
Amsoil SS 0W-40

 

[AFMoulton]

With 35" tires I'd do a 4.88 gear.

Stock size 4.56s.

Both will be a huge improvement over the 3.73s. As suggested, with what your asking from the 6.4, 5.13s may not be a bad idea. 12k is a heavy rig.

That's probably close to double what my tt weighs. My truck pulls my rig wonderfully and I know I could go another 2k in loaded trailer weight no problem. But 6k more, to me your in diesel territory, so I can see why your looking to regear.

As an aside, I've recently had a conversation with another member that leads me to believe that the rear axle in 2500 starting in 2018 or 2019 may not be the same as 3500 srw.

Check your driver's door sticker. My truck, produced in 12/16 has a 6500 GRAWR. So that should be the same as 3500 srw.

If your GRAWR is 6000 you may have a different (lighter duty) rear axle. I haven't confirmed that yet however. Something to think about though as I believed that after the 2014 hd update, the only difference between 2500 and 3500 are was the rear springs. But that may not be the case.

My ‘18 has a 6500# RAWR.


2018 Ram 2500 6.4L 4x4
Amsoil SS 0W-40

 

[GsRAM]

My ‘18 has a 6500# RAWR.


2018 Ram 2500 6.4L 4x4
Amsoil SS 0W-40

Good deal. It may have been when the 2019s came out. But glad yours has the heavier axle like mine

 

[AFMoulton]

Good deal. It may have been when the 2019s came out. But glad yours has the heavier axle like mine

Me too, I had to run outside and look when you posted that


2018 Ram 2500 6.4L 4x4
Amsoil SS 0W-40

 

[Bldrinker]

How loud is the whine?

I’m thinking about a aftermarket muffler and to hide the noise.

With the radio off it would drive you nuts.

 

[dhay13]

Mine and my sons 2018 2500 has a 6500lb GRAWR and both have 4.10's. We just towed my sons 8100lb TT 1400 miles and it towed very easily but it was mostly flat ground. Doubt we would have had any trouble even with a 10,000lb TT

 

[AFMoulton]

Mine and my sons 2018 2500 has a 6500lb GRAWR and both have 4.10's. We just towed my sons 8100lb TT 1400 miles and it towed very easily but it was mostly flat ground. Doubt we would have had any trouble even with a 10,000lb TT

It does just fine with 10,000. I just want it to do a little better which is why I’m going 4.88s with stock size tires.


2018 Ram 2500 6.4L 4x4
Amsoil SS 0W-40

 

[mtofell]

Doesn’t change the fact that payload matters.


2018 Ram 2500 6.4L 4x4
Amsoil SS 0W-40

Yeah, so does the balance in your IRA, your kid's grades and your cholesterol count but we don't need to talk about them all in every thread. The question was about G E A R S.

I keep re-reading the OP's post and just can't find the question about payload.

 

[AFMoulton]

Yeah, so does the balance in your IRA, your kid's grades and your cholesterol count but we don't need to talk about them all in every thread. The question was about G E A R S.

I keep re-reading the OP's post and just can't find the question about payload.

Guess if he didn’t want someone to bring up payload he should have left out his trailer weights.

But hey, what do we know.....


2018 Ram 2500 6.4L 4x4
Amsoil SS 0W-40

 

[RoadRamblerNJ]

5.13's
You won't regret it.

 

[RoadRamblerNJ]

NP man

Just trying to help from my experiences

Last thing.

Hemi owners (and all in the world today) need to not be so concerned about RPM being high. Cursing at 2,500 rpm all day in 5th i get better gas milage than crusing in 6th at 2000rpm.

Engines are not efficient below their power bands like the manufacturers want us to think. GET THEM RPM UP![emoji38][emoji38][emoji41][emoji1303]


Sent while firmly grasping my redline lubed RAM [emoji231]

Agree 100% on keeping the RPM's up!

You should maybe talk to a counselor about all that cursing you're doing. LOL.
Sorry, I had to.