AAM 12" Axle Gear Swap

[AH64ID]

Wow okay! I have never looked at my build sheet and it does say 11.5”. So that means I should be able to regear with the old 11.5” r&p gears? Does that also mean you could theoretically go to a 12” also?

Lastly, if you go to 4.88 or 5.14 with the 11.5 r&p is there something special to do to make the 4.88 or 5.14 to work with the 12” housing? Bushings/bearings/seals etc?

I would get with a company like Randy’s Ring and Pinion with your questions. That’s their specialty.

 

[drichardjackson]

I would get with a company like Randy’s Ring and Pinion with your questions. That’s their specialty.

Randy’s is what pushed me to find this thread. They say it can’t currently be done but I’m wondering if that was just that they haven’t seen a gas 2500 2020.

 

[AH64ID]

Randy’s is what pushed me to find this thread. They say it can’t currently be done but I’m wondering if that was just that they haven’t seen a gas 2500 2020.

When did you talk to them? Their website shows 4.44’s.

 

[drichardjackson]

The 4.44 will definitely work for either the 12" or the 11.5". However, I already have 4.10s and I really want to run 37's and get back to stock or higher overall ratio. So, I would need 4.88s or 5.13s.

 

[jsalbre]

The 4.44 will definitely work for either the 12" or the 11.5". However, I already have 4.10s and I really want to run 37's and get back to stock or higher overall ratio. So, I would need 4.88s or 5.13s.

FWIW, 37s on 4.10s is the same ratio as 33s on 3.73s.

 

[snocam]

I'd love to have 4.44s swapped into my axles. 2020 2500 hemi. It's on 37s and 3.73s. It's not bad the way it is, and I use the truck like a truck. It's just difficult to get definitive answers on what combo is available right now these trucks. Also, it's tough to find a shop around here that could do a professional install.

 

[Jimmy Dean]

Yea and really for most I would imagine, a set of front 9.25” gears will be necessary too, which I haven’t seen in 4.44, only 4.10.

 

[drichardjackson]

Yea and really for most I would imagine, a set of front 9.25” gears will be necessary too, which I haven’t seen in 4.44, only 4.10.

Yukon has 9.25" gears but they aren't listed for the new ones as apparently it requires some massaging of the housing to make them fit? Shoot idk. There is a parts list to do this swap for a Power Wagon on 4.88 that was confirmed to work for that truck. But, I can't find the guy to reach out to him and see what exactly was required.

 

[MDethloff]

Is it confirmed that the 11.5 gears, or the 12.0 4400/5500 gears, will work in the 2019-24 HO 3500 12.0 axle?

I haven’t found any confirmation but there’s some positive commentary here about gears being available?

 

[BadRam3500]

Randy’s world wide has the gears in stock for the aam 12 inch . They were released 3 weeks ago .
You need a new carrier and it will work . They currently have 4.44 & 4.88. I have some 4.88’s at the shop waiting to be installed in the next couple of weeks . Hopefully it’ll help spin the 42’s

 

[MDethloff]

Randy’s world wide has the gears in stock for the aam 12 inch . They were released 3 weeks ago .
You need a new carrier and it will work . They currently have 4.44 & 4.88. I have some 4.88’s at the shop waiting to be installed in the next couple of weeks . Hopefully it’ll help spin the 42’s

That's phenomenal news. I've been comparing measurements between the 4500/5500 banjo axle and the 3500 12.0 beam axle, and surprisingly, it looks like the gears and bearings are an exact fit between them. It looks like there might be a 7mm difference in bearing width that may require a spacer or different carrier. I was about to order a set of 4.44's from Yukon to test it out, but if Randy's has them, then heck yeah.

 

[MDethloff]

Randy’s world wide has the gears in stock for the aam 12 inch . They were released 3 weeks ago .
You need a new carrier and it will work . They currently have 4.44 & 4.88. I have some 4.88’s at the shop waiting to be installed in the next couple of weeks . Hopefully it’ll help spin the 42’s

Do you have any links or part numbers?

 

[johanh13]

What the heck are you guys doing with 4.44 gears? Pulling sleds at county fairs?
You'll be all out of RPMs at 70 MPH

I have 3.73 gears and 35" tires, running 1,700rpm at 75MPH. With 4.44 gears (~19% change) I would be running about 2,000rpm at 75MPH. Hardly running out of RPMs ?

 

[MDethloff]

I believe that I've narrowed the info down with mixed news.

The AAM 4.44 and 4.88 gears exist on the market.
Going below 4.10 requires a carrier change.

The part AAM 40193802 (Mopar 68462732AA) is the carrier for the 4500/5500, 33-spline axles, for 4.44/4.89 gears.
The part AAM 40193801 (Mopar 68455342AA) is the carrier for the 4500/5500 and 3500 dually, 33-spline axles, for 3.37/4.10 gears
The part AAM 40193800 (Mopar 68455344AA) is the carrier for the 3500 SRW, 30-spline axles, for 3.73/4.10 gears

Carriers:

CHRYSLER/DODGE > CHRY 12" REAR > POSI & LIMITED SLIP

POSI & LIMITED SLIP

www.drivetrainspecialists.com

Axle Components: Differential Cases - Traction Enhancing | American Axle & Manufacturing | Aftermarket OE Parts

AAM differential cases are machined and assembled to the high quality standards and tolerances that OEM's require. All case and case assemblies are designed and tested for each specific vehicle application. Low pinion flange run out, a key specification, is assured for maximum quietness.

demandaam.com

Gears:

2019+ Dodge Ram 4500 5500 12.0 Banjo 3rd Member Style 4:44 Ring & Pinion Gearset | C&M Gearworks

*** Containes note: "Please note that there is a case break between 4:10 and 4:44, so these can’t be used in a 3500 series truck."

I believe what this means is that:
- If you have a dually, you can grab p/n AAM 40193802 (Mopar 68462732AA), grab factory AAM 4.44 or 4.88 gears, and bolt everything together.
- If you have a SRW, you are stuck with the factory AAM 3.73 and 4.10 gears and cannot go deeper. This is because, while it seems the deeper ratio carrier will fit in the diff housing, it will have a 33-spline connection for the axle shafts, and the SRW truck uses 30-spline shafts. The 33-spline axles for the 3500 DRW and for the 3500 C&C are both different ( could be wrong about the C&C ones, but I'd be shocked if they were the same length/dims as the 30-splines).

What I do not know is:
- If you can take your existing 3500 SRW carrier and machine it, or make a spacer for it, to fit 4.44/4.88 gears.
- If the factory carrier in your truck has the splines only in the spider gears, or in the case itself as well. If the splines are only in the spider gears, then presumably you could swap your existing spider gears into the new carrier and run 30-spline axles.

 

[MDethloff]

I've spoken with Randy's. It sounds like they have gears for the 4500/5500 bajo/salisbury axle, but not the 3500 beam axle. They have a LSD carrier, but it's 33-spline (DRW).

Randy’s world wide has the gears in stock for the aam 12 inch . They were released 3 weeks ago .
You need a new carrier and it will work . They currently have 4.44 & 4.88. I have some 4.88’s at the shop waiting to be installed in the next couple of weeks . Hopefully it’ll help spin the 42’s

Could you share any details or p/n's? I'd love to know how to get gears into the SRW 3500 trucks.

 

[MDethloff]

Update:
The SRW 3500 can run the DRW gear carrier by swapping your existing spider gears into the new case. This is what Yukon said we would have to do with their new 4.44-4.88 ratio carrier.

I have not been able to confirm this but it seems like the C&C gears and carrier might fit into the 3500 SRW, with just a spider gear swap.

 

[4x4ready]

Update:
The SRW 3500 can run the DRW gear carrier by swapping your existing spider gears into the new case. This is what Yukon said we would have to do with their new 4.44-4.88 ratio carrier.

I have not been able to confirm this but it seems like the C&C gears and carrier might fit into the 3500 SRW, with just a spider gear swap.

That would be awesome, please share if you get any confirmation. I also reached out to Randy's / Yukon. Been checking back in since late 2022 on this. I have both 40" BFG HD Terrains and 42" Toyo's I plan to use if can get the any gears higher then 4.10.

 

[MDethloff]

That would be awesome, please share if you get any confirmation. I also reached out to Randy's / Yukon. Been checking back in since late 2022 on this. I have both 40" BFG HD Terrains and 42" Toyo's I plan to use if can get the any gears higher then 4.10.

Yukon has gears and carriers for 4.44-4.88 gears, you have to call in because some of them are not on the site yet. They just released a few weeks ago. We're looking at the exact same tires, probably the 42's!