6.4 hemi, 4.56 gears, speed and RPM's

[U&A]

Ivnever had my truck over 90[emoji23]

And when i was at 90 it was for like 10 seconds


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[AFMoulton]

I was passing someone on a two lane here in NM and looked down and it was at 100, holy ****, LoL.


2018 2500 6.4 4x4 4.10 Amsoil SS 0w-40, Softopper
Black Rhino Armory 18x9 +12mm
Cooper Stt MAXX LT295/70R18

2016 Durango 5.7 AWD 3.07 Amsoil SS 5W-30
1996 Nissan Altima 2.4 Amsoil SS 5W-30

 

[RoadRamblerNJ]

Update: It's February. LOL

UPDATE:
That's what happens when you stop working. LOL.

 

[RoadRamblerNJ]

I see no benefits to a drain plug. The cover should come off every time anyway to inspect the gears.

That is JMO^^^

This is a fact \/\/\/

And the shape of the OEM diff cover is like that for a reason. That half moon shape you see on the OEM cover. Its there so the ring gear can shoot gear oil right up it and that shape directs the oil up and over the ring gear and forward to the pinion gear to lube it.....it also ads in sending oil to the channels that direct oil to the the bearings.

No aftermarket diff cover mimics that shape.

My OEM cover is staying on.


Watch banks videos on the covers. I honestly dont like the man much but what he explains makes complete sense

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True.
Don't try to out engineer the engineers.
It's expensive and usually pointless. Cover comes off when oil is changed.

 

[RoadRamblerNJ]

I was passing someone on a two lane here in NM and looked down and it was at 100, holy ****, LoL.


2018 2500 6.4 4x4 4.10 Amsoil SS 0w-40, Softopper
Black Rhino Armory 18x9 +12mm
Cooper Stt MAXX LT295/70R18

2016 Durango 5.7 AWD 3.07 Amsoil SS 5W-30
1996 Nissan Altima 2.4 Amsoil SS 5W-30

Ahhhhh, only 4 more and you feel the power just drop out. It pulls right to 104 then just stays there. Never see 105. Did it , don't want to do it any more.
PS: Did this on Rt 287 N in North Jersey. No Police the last 15 miles before the NY state line. I was Going to work.

 

[GA Cattle]

Here's a little chart I made. I'm running 4.10's with 33's (275/70R18) stock size. I used a RPM calculator off of one of the gear sites I looked at. Your going to be approximately 150 rpm lower than these numbers with your 35's and 4.56's.


4th Gear, RPM's
R&P 60mph 65mph 70mph
4.10 2505 2713 2922
4.56 2786 3018 3250
4.88 2981 3230 3478

5thGear, RPM's
R&P 60mph 65mph 70mph
4.10 2054 2225 2396
4.56 2284 2475 2665
4.88 2445 2648 2852

6thGear, RPM's
R&P 60mph 65mph 70mph
4.10 1553 1682 1812
4.56 1727 1871 2015
4.88 1848 2002 2156

I believe I'm reading this correctly, you calculated the RPM's based off the stock tire size correct?

 

[U&A]

I believe I'm reading this correctly, you calculated the RPM's based off the stock tire size correct?

Yes,

33’s are stock tire hight.


Sent while firmly grasping my redline lubed RAM [emoji231]

 

[cuttymcgavin]

Hey everyone, been reading up on all the posts related to re gearing and the 6.4 hemi. I am very close to pulling the trigger on some yukon or aam ring and pinions 4.56's. I currently have the stock 3.73 and I have the stock tires and rims, I believe 20"
I am doing this to increase towing capacity so I can jump from my current 9K TT to a 13K fifth wheel. Getting quotes now, much on the higher side that what I am reading on posts a few years back, but looking between $2600-$3000. Any new feedback on your outcomes? One guy told me I wouldn't be able to go over 65 mph with those gears!?! I cant picture why or if that is even true. Hit me up with some feedback so as to help me finalize my decision!!

 

[NewBlackDak]

Hey everyone, been reading up on all the posts related to re gearing and the 6.4 hemi. I am very close to pulling the trigger on some yukon or aam ring and pinions 4.56's. I currently have the stock 3.73 and I have the stock tires and rims, I believe 20"
I am doing this to increase towing capacity so I can jump from my current 9K TT to a 13K fifth wheel. Getting quotes now, much on the higher side that what I am reading on posts a few years back, but looking between $2600-$3000. Any new feedback on your outcomes? One guy told me I wouldn't be able to go over 65 mph with those gears!?! I cant picture why or if that is even true. Hit me up with some feedback so as to help me finalize my decision!!

These transmissions are geared crazy for mileage. Taller gears will only put you in the higher power output range for the Hemi. They’re not diesels or old school big blocks.

I’m on 4.10 on stock tires, and travel up to 85mph(open highway speed limit around here). Do you really think the extra 300RPM that 4.56 gear adds would mean you can’t do 65?


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[Elkman]

The engine produces peak torque at 4,000 RPM's so having the gears and tires keeping it under 2,000 RPM's is like throwing away half the power of the engine. If you look at peak horsepower the situation is even worse as the engine peaks at 5,600 RPM's. By the way, this information is helpful when towing or carrying a heavy load.

Swapping 3.73 gears for 4.56 gears will only make an already very bad setup all that much worse.

 

[McBroom]

Here's a little chart I made. I'm running 4.10's with 33's (275/70R18) stock size. I used a RPM calculator off of one of the gear sites I looked at. Your going to be approximately 150 rpm lower than these numbers with your 35's and 4.56's.


4th Gear, RPM's
R&P 60mph 65mph 70mph
4.10 2505 2713 2922
4.56 2786 3018 3250
4.88 2981 3230 3478

5thGear, RPM's
R&P 60mph 65mph 70mph
4.10 2054 2225 2396
4.56 2284 2475 2665
4.88 2445 2648 2852

6thGear, RPM's
R&P 60mph 65mph 70mph
4.10 1553 1682 1812
4.56 1727 1871 2015
4.88 1848 2002 2156

How would this chart look if I were running 37’s on 4.56 gears???


- The Blue Mule

 

[wyo2track]

How would this chart look if I were running 37’s on 4.56 gears???


- The Blue Mule

Can I give you an educated guess...lol? I'd guess a 37 with 4.56's is going to put you at or slightly above the rpm levels of a stock tire with 3.73's. Like many other posts on this forum, its really not conducive to even consider 37's on anything but 4.88's or even 5.13's to actually lower the final drive ratio or get back to a stock tire on 4.10's rpm levels.

I've really considered re-gearing...hashed it out back and forth, but for only 15% of my drive time towing, just not worth it to me. I don't have much gripe with the way my 4.10's performs at speeds above 50 mph with my loads that are under 10K. The engine/tranny combo has just enough. Its that 2nd gear that really just sucks on our county roads that have speeds of 40 mph and under...I'd have to put in 4.88's to get peak torque in 2nd down to 44 mph from the 53 mph now. Well that'd be ok when towing, but the other 85% of my unloaded time on our 70 mph hwy's the truck would be less efficient.

If a 5th wheel trailer is in my future, I'm taking that $3000 to re-gear and my truck and going to find a nice used 6.7 CTD.

 

[NewBlackDak]

The engine produces peak torque at 4,000 RPM's so having the gears and tires keeping it under 2,000 RPM's is like throwing away half the power of the engine. If you look at peak horsepower the situation is even worse as the engine peaks at 5,600 RPM's. By the way, this information is helpful when towing or carrying a heavy load.

Swapping 3.73 gears for 4.56 gears will only make an already very bad setup all that much worse.

This is contradictory. You go on and on about needing more RPMs to get to the power, and then say gearing up to get those RPMs is no good.


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[Ratket]

When I eat crayons I make more sense..

 

[Bldrinker]

Looking at buying a toy hauler that has a gvwr of 13,500lbs.
I won’t max it out but 13,000lbs is likely.

I have an ‘18 6.4 with 4:10’s. If I’m not happy with the pulling performance I’m going to consider gears. I’m wondering if 4:56’s would put my first gear final ratio close to the new 8 speed?

after looking at the chart on the first page. I’m thinking 4:56 would be best. I tow at 60-65 tops. 4:88 might be to much?

how big of an improvement can I expect? If I’m going to spend $2500 I sure in the hell better notice it!

I’m on the west coast and pull some big hills. Cajon Pass and the hill from bishop to mammoth are the norm.

 

[Mountaineer83]

It isn't going to put your 1st gear near the new 8 speed, but it will help. The new 8 speed has a first gear of 4.71 while out 6 speed is 3.23.

I know what you want though in a lower 1st. My 5th wheel is 13,400 lbs empty per my unit specific sticker, so a lower 1st would be awesome.

I have the 4.10s and I am going to go 4.88 in the next couple months. My guy cant get to me until at least February.

 

[U&A]

Looking at buying a toy hauler that has a gvwr of 13,500lbs.
I won’t max it out but 13,000lbs is likely.

I have an ‘18 6.4 with 4:10’s. If I’m not happy with the pulling performance I’m going to consider gears. I’m wondering if 4:56’s would put my first gear final ratio close to the new 8 speed?

after looking at the chart on the first page. I’m thinking 4:56 would be best. I tow at 60-65 tops. 4:88 might be to much?

how big of an improvement can I expect? If I’m going to spend $2500 I sure in the hell better notice it!

I’m on the west coast and pull some big hills. Cajon Pass and the hill from bishop to mammoth are the norm.

4.88 are NOT to much IMO. Towing that weight the hemi NEEDS higher RPM. Dont be afraid of RPM if you want to tow heavy with a gasses HD.




Sent while firmly grasping my redline lubed RAM [emoji231]

 

[Bldrinker]

4.88 are NOT to much IMO. Towing that weight the hemi NEEDS higher RPM. Dont be afraid of RPM if you want to tow heavy with a gasses HD.




Sent while firmly grasping my redline lubed RAM [emoji231]

Not afraid of the RPM ideally I would want to be in fourth at 60-65mph. I was thinking the 4:88 might be to high and it would want to shift to fifth. Obviously I can lock out 5th and 6th.

I guess I could put in 4:88’s and if it’s to much rpm I could upgrade to 34’s.

 

[Ratket]

Looking at buying a toy hauler that has a gvwr of 13,500lbs.
I won’t max it out but 13,000lbs is likely.

I have an ‘18 6.4 with 4:10’s. If I’m not happy with the pulling performance I’m going to consider gears. I’m wondering if 4:56’s would put my first gear final ratio close to the new 8 speed?

after looking at the chart on the first page. I’m thinking 4:56 would be best. I tow at 60-65 tops. 4:88 might be to much?

how big of an improvement can I expect? If I’m going to spend $2500 I sure in the hell better notice it!

I’m on the west coast and pull some big hills. Cajon Pass and the hill from bishop to mammoth are the norm.

If in So Cal I would reach out to CjC off road, they have a lot of experience with the HD Rams, not so much the gassers but they should be able to assist. How ever I am sure you have your pick of drive line shops. I ran those Grades a lot in my previous 14 2500 mega 6.4. “ Sherwin,deadman,Conway, and ya the 6 speed is just Ill matched. If I kept my truck I was going to do gears likely 4.88. Keep us posted.

 

[Nickx86]

Tbh, I always go by axle upgrades as up 2 axle ratio difference. By going up one axle ratio isn’t worth the aftermarket cost and the performance difference