37" MTs with which gear, 4.88 or 5.13?

[WY.Ram]

2016 Power Wagon, 6.4L, 6 speed, 4.10, 34.5" MT Mickey Thompson.
CAI, ARH tubes w highflows to Solo, unlocked PCM w Hemifever tune, PC at WOT

We sleep at 6700' elevation and go uphill from there.

I'm getting ready to re-gear my Wagon in order to run 37" or 38" MT tires and would like to hear your experience with re-gearing your truck, what ratio you chose, and what ratio you would choose here?

If you're not running a lower gear ratio and a larger tire but you are a gear head, I would value your input as well!

Thank you

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[AFMoulton]

I’d go 5.13, I’ve read and heard it’s the best for these transmissions and big tires, feels/shifts like it should. I’m going 35’s and 4.88s. As soon as I have some coin!


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

 

[McBroom]

I recommend going with the 5.13’s and 38’s. You’ll have the best fun with this setup when your out wheelin around


I Love my 18 Ram 2500HD 4x4 CC
Blue Streak Pearl off-road

 

[Grand Mesa]

Saw that you stated sleeping at 6,700 feet for your regearing. My figuring is that boat V8 performance at high elevations and my Power Wagon V8 performance at the same high altitude are both impacted. I know that running a smaller propeller on my boat makes up for some of its loss power. Must be the same with running a higher gear ratio on the Power Wagon.

I live at approximately 6,000 feet and boat often on our nearby Vega Reservoir at an elevation of 7,700, Blue Mesa Reservoir at 7,500, and once in awhile on Flaming Gorge Reservoir at just over 6,000. I can feel a major power gain on Flaming Gorge due to its lower altitude. Had a seized steering cable issue while boating today, so my boating season is done with. It's a 1978 Mercruiser 305 two barrel carburetor V8 is rated at 198 horsepower at sea level, but has only approximately 148 horsepower on Vega. I run a much smaller propeller than one would at sea level in order to achieve approximately 4,200 RPM at WOT. Lowers my top speed to below 40 MPH versus 55 MPH the boat can do at sea level with a larger propeller, but at these higher altitudes the engine would lug if I didn't run a smaller propeller and it won't achieve between 3,800 to 4,200 RPM at WOT.

Figure it's the same with the Power Wagon 6.4L. Need a higher gear ratio number to make up for the horsepower loss at higher altitude, not even considering the larger tires. Double whammy. Best to go with a highest gear ratio just for the altitude. Sure a boat doesn't have a transmission with different gear selection, but even the Power Wagon has only a 1st gear low while towing on steep high altitude mountain pass and that's as low as it goes, especially needed around hairpin turns.

At 7,000 feet an approximately 400 horsepower engine like the Power Wagon would put out approximately 308 horsepower. At 10,000 feet it's around 274 horsepower. Above that it's even less. I tow above 10,000 feet often and the higher altitude does impact the performance even with its 34" ST Maxx tires (285 75R17).

https://www.robertson-marine.com/boatingintherockymountains.htm

 

[WY.Ram]

Thanks for the input. I ordered the 5.13s today, scheduled for Monday/Tuesday swap.

Here's a little tidbit that I was not aware of, even after reading as many gear swaps as I could (I probably missed it), but once I chose the 5.13 ratio then dude ordered the gear set he came back and told me that he was able to order the 5.13s in OEM parts (but no 4.88 OEM)! There should be essentially no gear whine after break in. Frosting right there.

Thanks again


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[bmhenry]

Thanks for the input. I ordered the 5.13s today, scheduled for Monday/Tuesday swap.

Here's a little tidbit that I was not aware of, even after reading as many gear swaps as I could (I probably missed it), but once I chose the 5.13 ratio then dude ordered the gear set he came back and told me that he was able to order the 5.13s in OEM parts (but no 4.88 OEM)! There should be essentially no gear whine after break in. Frosting right there.

Thanks again


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Which gear manufacture did you choose, AAM? For both front and rear diffs?

 

[WY.Ram]

I believe it is AAM. I guess I didnt realize there would be more the one manufacture of OEM gears for my truck and I didnt actually make a choice.

My axle / diff has AAM markings on it, and I sent every piece of information I could find to the shop so they could order the right set.

I sent them my VIN, the AAM number on diff, and a sticker with parts number info that was on axle, and I guess I assumed the OEM was AAM by default.

I'll follow up with the shop and find out. What other manufacturers could be in the mix for OEM production?


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[AFMoulton]

According to AAM website they don’t make anything but 4.10 for 14 and newer 2500. They make a 5.13 for 3500, but I am not sure it would work. I’m looking forward to seeing if this works because I want 5.13s!

I did find this though


http://www.justdifferentials.com/Dodge-Ram-Gear-Package-p/gpram2500-select.htm

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

 

[WY.Ram]

Hmmm, interesting info. Shop Dude did ask me if I had 11.5 or 11.8 rear diff. I have read the 11.8 is on the 3500, I think mine is a 11.5 (total guess) and maybe I read the 11.8 set will fit the 11.5.

None of what I am muttering is borne from experience. I have read it only. In an effort not to poison the information database with inaccurate yapping, I'm going to email the shop and ask a couple light questions.

The time is quickly approaching beer-thirty, so if they don't get back to me today, I will get this info asap and post. My truck goes in Monday and I'm scheduled to pick it up Tuesday so were going to know soon, but I wanna know now. Lol

I'll shout back


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[WY.Ram]

According to AAM website they don’t make anything but 4.10 for 14 and newer 2500. They make a 5.13 for 3500, but I am not sure it would work. I’m looking forward to seeing if this works because I want 5.13s!

I did find this though


http://www.justdifferentials.com/Dodge-Ram-Gear-Package-p/gpram2500-select.htm

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

These guys have been nothing short of extremely responsive throughout. So he told me they are the AAM and that I have the 11.5 diff. So, I am going to assume what I read somewhere here on RamF is the 11.8 (3500) gears work in the 11.5 (2500) diff. I will know that to be completely true or not on Tuesday and i will post it soon as know it.

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[bmhenry]

These guys have been nothing short of extremely responsive throughout. So he told me they are the AAM and that I have the 11.5 diff. So, I am going to assume what I read somewhere here on RamF is the 11.8 (3500) gears work in the 11.5 (2500) diff. I will know that to be completely true or not on Tuesday and i will post it soon as know it.

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Just so you know WY. RAM.. WE are watching you!! and eagerly waiting an update.

 

[WY.Ram]

Just so you know WY. RAM.. WE are watching you!! and eagerly waiting an update.

Lol, I had a nice little tidbit for you all yesterday and by the time I dealt with life, it would have been a breakfast treat. I'll get back to that in a sec.

Al owner of Colorado Gear and Axle just called me 5 minutes ago. He told me the gear swap is done, everything seems to be in excellent order right now but hes going to take my wagon out for a drive, then call me in to grab my truck. I am 2.5 hrs away right now and told him I'm just gonna head that way. He said I had to wait as to make sure that his test drive goes well, hes gonna go spin that driveline mach one. He's earned it.

Here's the short summary:

Swapped out the original 4:10 gears with the 5.13 ratio. Current 34.5" MTs jave 37k miles and 9/32 tread left. I plan on 4/32 tread by end of day. Then new treads 36.5 to 38.5 depending on how low the gearing feels on these 35s when I pick it up.

The cost for the job was a cool $2700 plus tax, with $500 down. The turn around time was less 24 hrs.

The gears are OE from AAM. Al couldn't say enough positive comments towards AAM vs after market gear sets. If a choice is offered even a slightly different ratio, AAM is the only way.

I am going to try to upload the pic I took of the gear set bar codes and part numbers on the box for both, front and rear. The box actually list the 5.13 gear set for the (2500) 11.5 rear diff, and 9.25 front diff.

I think if they'd just do that on their website our confusion would be mitigated.

Smokin 35" tire pic coming later. Remember I'm at 6700 feet elevation, turning 35s over in an 8500 lb beast doesn't happen very often.

I can hardly wait to test 4Lo, I already can barely stop the truck when in Lo.

Also, no grinding on housing to fit the gear, stock diff covers.

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[bmhenry]

There WE GO! Thanks for the update.. If you would not mind advising what the RPM is doing 70mph for us stockers to compare. I'm running 37s currently with the 4.10.

Now, only to find a good shop here in Missouri. Anybody know of one or have recommendations?

 

[AFMoulton]

**** yeah!!!


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

 

[bmhenry]

Come on!! We need more info. We want to hear back from you after the pick of the truck. Also, what was the Part number one the 9.25 gear set?

Where is the slot to insert more dollar bills, for the show/info... I mean.... uh... Bye.

 

[WY.Ram]

Fuuuuuk, I feel like an *******, I am sorry. What's crazy is I've spent almost the whole time away thinkig of all the cool **** I was gonna say about the 5.13s, all the way home, all night all morning, missed your post, reached for phone, and key board several times than whammi, wife mind f.... me again. And zeroed my cognitive abilities like a ninja bits. Aaaahhhhhhh.

TRUCKS, Gears and skinny pedal. Ok I've got all you wish for. Let me start by quoting *****'s post above:

**** yeah!!!


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

With extra emphasis on the; **** Yeah, LOUDER *** YEAH.

Ok ill chill with profanity sorry. Very Very exciting , my Puthie Wagon is like a screaming beast.

So much more to say but I want you to know it's coming right now but I'll post this so you know I'm not a total inconsiderate douche. I have the 9.25 part number and I have rpm tables from before and after gear swap, every 5mph for 4, 5, and 6th gear. Well starting at 60 to 80mph. K

Sorry for lag, really. But I have nothing but badass news. You really should come drive it, ya got drive it.
All I want to do is go drive,.now is my opportunity but this is way important I will post instead of going out to play and hope you will forgive this douche dude. Numbers a coming bro.

One more time: *** YEEEAAAHHHHHHHH

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[WY.Ram]

Ok here is another pic of both labels in their entirety.

Oh holy ****, the 95 is the wrong box, It has 3.42 as the gear ratiO. he Musta re boxed my 4:10 in wrong box. Dammit. I will email him tonight and request. He'll hit me back early, and I won't douche out on ya

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[AFMoulton]

LoL awesome! Burnout video to come soon right?!?


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

 

[WY.Ram]

LoL awesome! Burnout video to come soon right?!?


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

Burn Out vid to come soon, Ya know they have this dumb thing called a "break in" procedure, Some thing about 65 mph maX, no hard pedal, Heavy towing and no long distance, but I did not hear "no burnout vids".
who's available tonight, I need a videographer, Next.

Alright, I mighta missed a speed reading here or there but I wi ll go out and remeasure any range from the 5,13 set. II'll make up a number for same request on 4:10.

2016 2500 6. 4L 6 Speed 66 RFE, Tires are Mickey Thompson MT sold as 35", right now as the speed/rpm readings are recorded the tire measures 33.75". measured from ground to top of tire using a tape measure and a level on top the tire.

5:13 diff gear set:

Tranny 4th gear
60 miles an hour 2950 RPM
65 miles an hour 3330 RPM
70 miles an hour 3550 RPM
75 miles an hour 3815 RPM

Tranny 5th gear
55 miles an hour 2280 RPM
60 miles an hour 2450 RPM
65 miles an hour 2680 RPM
70 miles an hour 2890 RPM
75 miles an hour 3100 RPM
80 miles an hour 3300 RPM

Tranny 6th gear
65 miles an hour 2082 RPM
70 miles an hour 2200 RPM
75 miles an hour 2400 RPM
80 miles an hour 2550 RPM

4:10 Diff Gear
Tranny 5th gear
85 miles an hour 2785 RPM
80 miles an hour 2650 RPM
75 miles an hour 2475 RPM
70 miles an hour 2345 RPM

Tranny 6th gear
85 miles perhour 2094 RPM
80 miles an hour 2010 RPM
75 miles an hour 1880 RPM


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[bmhenry]

must post pics or a video - otherwise it never happened. LOL.. please - forego the video and break in the gears properly; I hate to see good money wasted.