JTDR with 373 Conversion to 488: Requires Entire Front Axle Changeout

[Digger 5]

The prior generation of these axles DID require a carrier change. This version in the JT does not.
I have a chart that shows the break - assumed it was for these since the numbers were the same, but no, these don't require a carrier swap.
Maybe they are thinking of the other version or prior generation of this axle?

Supposedly this is for the pre-AdvanTec axles the JT has -

FWIW- The prior generation of these axles DID NOT require a carrier change. The JK 44's could go from 3.21 to 5.38. The generation PRIOR to the JK (the TJ except TJ Rubicon) did require a carrier change.
It's worth noting that the front JL 30 doesn't need a carrier change either although all prior models did require the change. The factory 3.45 JL gear is an ultra thin gear and the diff will allow fit of even 5.38 gears.

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[MOPAR Boy]

FWIW- The prior generation of these axles DID NOT require a carrier change. The JK 44's could go from 3.21 to 5.38. The generation PRIOR to the JK (the TJ except TJ Rubicon) did require a carrier change.
It's worth noting that the front JL 30 doesn't need a carrier change either although all prior models did require the change. The factory 3.45 JL gear is an ultra thin gear and the diff will allow fit of even 5.38 gears.

So, the bottomline to change from 373 to 488:
1-A new carrier is definitely required
2-It will fit in the existing differential case
3-The 488 ring and pinion set will also fit inside the existing diff
3-Therefore, the existing front axle (and its front diff) is fine, as is, so long as a new cxr is ordered, and a complete master install kit is also ordered?

 

[ShadowsPapa]

So, the bottomline to change from 373 to 488:
1-A new carrier is definitely required
2-It will fit in the existing differential case
3-The 488 ring and pinion set will also fit inside the existing diff
3-Therefore, the existing front axle (and its front diff) is fine, as is, so long as a new cxr is ordered, and a complete master install kit is also ordered?

No, he's saying correctly that this generation and the one immediately before it did not.
I'm trying to find the exact break as some of the "gear shops" have conflicting information, but the bottom line is that the JT does NOT require a carrier change or a housing change.

You need the gear set, bearings, seals, shims, etc. (so a master install kit) - no carrier is needed.
A good shop could put 4.xx gears into the housing you have and use the existing carrier.

Even in the prior generations, there were "thick" gear seat that allowed using the original carrier.

 

[MOPAR Boy]

No, he's saying correctly that this generation and the one immediately before it did not.
I'm trying to find the exact break as some of the "gear shops" have conflicting information, but the bottom line is that the JT does NOT require a carrier change or a housing change.

You need the gear set, bearings, seals, shims, etc. (so a master install kit) - no carrier is needed.
A good shop could put 4.xx gears into the housing you have and use the existing carrier.

Even in the prior generations, there were "thick" gear seat that allowed using the original carrier.

OK, that’s great news! That will definitely save me some $’s!

I was just reading in the 2021 Jeep Gladiator Mopar JPP accessories catalog under the description for the ‘JPP Ultimate Dana 44 AdvanTEK axle assembly,’ it says: ‘…The high-clearance carrier design adds an additional half-inch of ground clearance, and an expanded range of gear ratios (4.56, 4.88, 5.13, and 5.38) helps accommodate for a variety of tire sizes…’

So, my takeaway is JPP is describing the OEM axle equipped on all of the 2018+ Rubicons with the new wide M210, so there’s really nothing to be gained by going with an entirely new crate axle, other than I guess if someone wants to eliminate FAD, in order to get rid of the spliced axle on the passenger side (assuming that’s an advantage in the first place)? This also means all 2018 and up Rubi’s gained a half-inch of ground clearance, given the new M210 wide front OEM axle, and it’s new diff case?

 

[Digger 5]

I was able to get confirmation-
The JT m210 front 3.73 gear set uses the same diff case as the 4.10 case.
We already had confirmation on the rear m220. m220 3.73 gears will use the 4.10 case as well.

 

[ShadowsPapa]

I was able to get confirmation-
The JT m210 front 3.73 gear set uses the same diff case as the 4.10 case.
We already had confirmation on the rear m220. m220 3.73 gears will use the 4.10 case as well.

Yeah, that's been posted here because a few Overland owners have already changed gears - as well as some sport (non max tow) owners have done same. So it was a given the SAME housing will support any of the common gear ratios.
Can't change the rear and not change the front.
I asked the folks here last year - and we discussed carriers as well. The proof then was that several had already made the change.

 

[Slyboots2313]

It was asked once but the OP didn’t answer… why in the heck would you go 4.88s with the Diesel??

I plan to regear my diesel as well when I jump from 35s to 37s but my research has shown 4.10 or MAYBE 4.56. Going 4.88 is extreme. That’s what people are doing on 37s with the gasser.

I have see plenty of people say you don’t need to re-gear with the diesel because of all that torque. I plan to regear because I bought the diesel for all the torque. I don’t intend to lose all of that fantastic torque by leaving gears at 3.73s! I want to rock my diesel with 37s like it’s rolling on stock sport tires. Not like it’s a gasser on stock 33s.

OP is worried about 1:1 scenarios on whether he should replace the entire axle for gears (what?!), but is moving to 4.88s based on gas engine performance and not diesel, which is not 1:1 scenario. Logic is par for the course in 2021.
A lot of great advice was given by this community of experts, but not received. There’s more collective knowledge on Jeeps in this forum than a dealership that sells dozens of brands and models. Surprised no one even touched the “warranty” BS.

 

[tampahoosier]

OP is worried about 1:1 scenarios on whether he should replace the entire axle for gears (what?!), but is moving to 4.88s based on gas engine performance and not diesel, which is not 1:1 scenario. Logic is par for the course in 2021.
A lot of great advice was given by this community of experts, but not received. There’s more collective knowledge on Jeeps in this forum than a dealership that sells dozens of brands and models. Surprised no one even touched the “warranty” BS.

Yeah, I don't bother with the warranty stuff when it comes to comments. Everyone says "The Magnuson act" is going to protect you. Bullshit, it's up to you to hire a lawyer and go to court for it. I have reason countless issues on FB groups where the Magnuson act was a bunch of words and nothing more and the person lost out.

 

[Wildlifeguy]

There is another option to consider if the dealer is set on only replacing the entire assembly. I have not priced a new entire mopar assembly, so I'm not sure how this would work on paper including labor. Have them install the new assembly and keep/sell the old one. I'm willing to bet the assembly even with 3.73 gears would sell quickly for a decent price. It's not exactly the same, but for example, for my TJ, I found some takeoffs with gearing I wanted. I did the swap in my driveway by myself and sold the old 30 and 35 (pathetic 3.07 gearing) within a few days of advertising. When I was searching for assemblies, they didn't last on the market for more than a few days. My overall total cost for the "new" axles and gearing was less than $350.

 

[Slyboots2313]

There is another option to consider if the dealer is set on only replacing the entire assembly. I have not priced a new entire mopar assembly, so I'm not sure how this would work on paper including labor. Have them install the new assembly and keep/sell the old one. I'm willing to bet the assembly even with 3.73 gears would sell quickly for a decent price. It's not exactly the same, but for example, for my TJ, I found some takeoffs with gearing I wanted. I did the swap in my driveway by myself and sold the old 30 and 35 (pathetic 3.07 gearing) within a few days of advertising. When I was searching for assemblies, they didn't last on the market for more than a few days. My overall total cost for the "new" axles and gearing was less than $350.

I think the problem with these new axles is the Front Axle Disconnect. It really limits who would be interested in purchasing. It’s too much tech to swap into a non-JT/JL build, and the FAD itself is a weak point for “serious” builds.

 

[MOPAR Boy]

I think the problem with these new axles is the Front Axle Disconnect. It really limits who would be interested in purchasing. It’s too much tech to swap into a non-JT/JL build, and the FAD itself is a weak point for “serious” builds.

Why would no FAD limit interest for someone with a 2018+ JT with the wide M210? My understanding is the only con with no FAD is your mpg might decrease, like about one-tenth of a mile per gallon. I doubt very may folks running 37's would give a rip about such a small decrease in MPG. What am I missing here?

 

[Free2roam]

From what I've read on the forums here. You don't need to change the gearing at all if only going to 37's. Especially if it's a diesel.

 

[Slyboots2313]

Why would no FAD limit interest for someone with a 2018+ JT with the wide M210? My understanding is the only con with no FAD is your mpg might decrease, like about one-tenth of a mile per gallon. I doubt very may folks running 37's would give a rip about such a small decrease in MPG. What am I missing here?

I think you have my point backwards. It’s the presence of the FAD that would limit interest. If there was no FAD you’d have tons of interest in a beefy D44 axle that can be swapped into all kinds of vehicles. It becomes a niche market w the FAD.

 

[MOPAR Boy]

OK, gotchya. You’re saying the Rubi market with M210 is just too small. I get that point, but my understanding is the HD AdvanTEC M210 crate axle (without FAD) is made for a lot of vehicles other than just the Jeep JT/JL, which is why there is no FAD on that product in the first place.

 

[Shoebox]

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