RHO gears… for trx

Fifty · Jan 18, 2025

As trx owners, We really need to embrace the RHO guys.

Together we will be able to entice manufacturers to make parts.

Separately we just don’t have enough off-roaders right now

PhoenixTRX · Jan 18, 2025

FULLTHROTTLERICK said:
I'd kill for a front ELSD. The BLD is pretty good on these trucks but man a true LSD with no brake vectoring would be sick

Side note: I reached out to 74weld about Rex portals just for S&Gs and never heard back.

It's just a matter of time before some 'Crazy Ivan' rebuilds a salvage TRX....
.... then does eccentric stuff like Unimog Portals and SHERP flotation tires/CTIS wheels.

FACT.

FULLTHROTTLERICK · Jan 18, 2025

PhoenixTRX said:
It's just a matter of time before some 'Crazy Ivan' rebuilds a salvage TRX....
.... then does eccentric stuff like Unimog Portals and SHERP flotation tires/CTIS wheels.

FACT.

But will he rebuild just for himself or make a few of us some killer one-offs?

Two · Jan 18, 2025

Fifty said:
Oddly enough, having two overdrive gears, when you step up in gearing you actually get better mpg…
But when you go to far in gearing that’s where the mpg take a hit.

I’d bet we would gain a mpg or two until we pass 4.5x gears

I must not be driving slowly enough.

A 9th gear would be great I think, much like it would've been in the Trackhawk. Seeing the tach way up there for no reason does nothing for me.

PhoenixTRX · Jan 18, 2025

FULLTHROTTLERICK said:
But will he rebuild just for himself or make a few of us some killer one-offs?

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DirtMcGirt8732 · Mar 12, 2025

Revival bump.

68588571AB is indeed the correct part number for the RHO front diff. BAM Wholesale checked it against an RHO VIN and confirmed it was correct. It’s still not available.

I also checked with them on the rear gears. The ring and pinion gear kit for those is not listed in the catalog currently. BAM put in an inquiry with Mopar to see if it’s available separately from the axle. I’ll update when I hear back from them.

DirtMcGirt8732 · Mar 13, 2025

Per Mopar, the part number for the rear ring & pinion gear set is 68658132AA.
Looks like it’s currently available for about $500.

https://www.bamwholesaleparts.com/oem-parts/mopar-center-differential-gear-kit-68658132aa?origin=pla&srsltid=AfmBOopjlAdJ1x7HIeAnt1_oskrMieSoJJh2p5HjLrABmcF5zKaj2ueY

T-bone · Mar 13, 2025

DirtMcGirt8732 said:
Revival bump.

68588571AB is indeed the correct part number for the RHO front diff. BAM Wholesale checked it against an RHO VIN and confirmed it was correct. It’s still not available.

I also checked with them on the rear gears. The ring and pinion gear kit for those is not listed in the catalog currently. BAM put in an inquiry with Mopar to see if it’s available separately from the axle. I’ll update when I hear back from them.

isnt the front diff the same as the regular 1500? wouldn't a front diff from a rebel or any 3.92 ram work?

Dubstep Shep · Mar 14, 2025

DirtMcGirt8732 said:
Revival bump.

68588571AB is indeed the correct part number for the RHO front diff. BAM Wholesale checked it against an RHO VIN and confirmed it was correct. It’s still not available.

I also checked with them on the rear gears. The ring and pinion gear kit for those is not listed in the catalog currently. BAM put in an inquiry with Mopar to see if it’s available separately from the axle. I’ll update when I hear back from them.

Looks like some places are starting to sell it. No idea if it's actually in stock or not though.

Dodge Parts Overstock

DirtMcGirt8732 · Mar 15, 2025

Dubstep Shep said:
Looks like some places are starting to sell it. No idea if it's actually in stock or not though.

Dodge Parts Overstock

Yeah, this is the only place that showed them available when I was looking. I think it’s probably a they’ll probably take your money and then ship when they become available situation versus them being the only ones that have it.

DirtMcGirt8732 · Mar 15, 2025

T-bone said:
isnt the front diff the same as the regular 1500? wouldn't a front diff from a rebel or any 3.92 ram work?

I thought about this too. I think they’re probably different, but don’t know for sure. Maybe someone smarter than myself can chime in lol

OnTheReel · Mar 15, 2025

Regular 1500 front diffs are different because they have the center axle disconnect and we don’t.

Dubstep Shep · Mar 17, 2025

DirtMcGirt8732 said:
Yeah, this is the only place that showed them available when I was looking. I think it’s probably a they’ll probably take your money and then ship when they become available situation versus them being the only ones that have it.

Yea seems likely, I plan on waiting until either a wrecked RHO comes up locally or one of the big store I usually buy from start carrying them.

RamTrxUSA · Mar 17, 2025

Would you need to tune the transmission?

Dubstep Shep · Mar 20, 2025

RamTrxUSA said:
Would you need to tune the transmission?

I wouldn't think so. You shouldn't even need to recalibrate the speedo since the truck uses the wheel rpm to calculate speed.

Fifty · Apr 1, 2025

Most vehicles now use two speed sensors. Wheel speed sensors and the sensor in the trans.
So you may correct the speedo but the t/c and abs and speed limiter think it’s the old gearing.

Maybe those with alpha obd or the factory manual could confirm.
Or if someone has a copy of the ram rebel tune and the trx tune if there is a difference in the tire/gear wizard

Dubstep Shep · Aug 21, 2025

Okay, found the part number for the RHO rear axle and gears. I pulled these from one that was on the lot at the dealer that was doing repairs on my truck when I picked it up today.

Rear ring and pinion: 68658132AA
Rear full axle assembly: 68585347AB

Both appear to be available online. The rear gears are pretty cheap, only like $500. Combine that with the front assembly at $1,300 and it looks like you could maybe get away with a 3.92 conversion for a little over $2k.

It looks like the front diff is still hard to find though, so that might be a problem. I'm going to keep an eye open for a wrecked RHO, but if that takes too long I may order the ring&pinion and front pumpkin and give this a try.

FULLTHROTTLERICK · Aug 21, 2025

Dubstep Shep said:
Okay, found the part number for the RHO rear axle and gears. I pulled these from one that was on the lot at the dealer that was doing repairs on my truck when I picked it up today.

Rear ring and pinion: 68658132AA
Rear full axle assembly: 68585347AB

Both appear to be available online. The rear gears are pretty cheap, only like $500. Combine that with the front assembly at $1,300 and it looks like you could maybe get away with a 3.92 conversion for a little over $2k.

It looks like the front diff is still hard to find though, so that might be a problem. I'm going to keep an eye open for a wrecked RHO, but if that takes too long I may order the ring&pinion and front pumpkin and give this a try.

Oh HELL YEA!! And if you did swap hardware, would you just use Tazer to adjust the axle ratio and be good to go or would something more intricate need to be done tuning/software wise?

Dubstep Shep · Aug 22, 2025

FULLTHROTTLERICK said:
Oh HELL YEA!! And if you did swap hardware, would you just use Tazer to adjust the axle ratio and be good to go or would something more intricate need to be done tuning/software wise?

I'd probably do it in HP tuners, but yea it's probably required.