Base Model Rear Locking Differential

[PSUTE]

Keep in mind that the term "Brake Lock Differential" is just marketing speak for brake-based traction control. Basically, the PCM notices that one wheel is slipping and applies that individual brake to arrest the slip. That's something that a lot of cars have had standard for years now. On a 4x4, you can call it a fancy name to make it sound like a substitute for a locker (which it isn't). In our case, Ford is at least calling it like it is:

This is taken from the list of standard features in the base model Bronco on the B&P page. See the 4th line down - Electronic Traction Control. That's it. It also goes hand-in-hand with the first line item, ABS w/ Electronic Stability Control. These are basically different facets of the same system.

Base squatch is the only way. Sucks...

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[Hoofnmouth]

When messing with gears is also important to keep the engine happy ,throwing to high a gear ratio kills performance ive seen trucks that could hardly get up hills,but they had 37s.
The other is too low,gears on my buddies manual were so short he would start off in 2nd gear, you have to find the happy medium 4,70s are going to be on the high end for 37s if its not great ill change them .

 

[wintoon]

TL : DR; I conclude then that installing a helical gear LSD to the M190 open front differential with a welded ring will require at least a new differential with bolt-on ring, and a ratio change, likely to 4.46 (the std on Badlands/Black Diamond with automatic transmission).

The search function does its job, most excellently here! The search police will be pleased. . .

I am a newbie to the world of off-roading. This has been a rich discussion of what appears to be a popular topic, of how to get more out of an open front differential on these beasts. I don't want or need the 35" wheels or front locker of the Sasquatch pkg, yet I am looking into paths to get the most capability from my 2 dr Outer Banks (or your base or Big Bend) drive train with rear locker, advanced transfer case, and 3.73 or 4.27 gears. I will also install 285/70 33" tires on 17 X 8 rims, because it's a good look.

My Bronco will be a daily driver, with off-road use limited to unpaved roads, forest trails, and off road on relatively smooth ground (no rock climbing or other technically intense activity). I conclude that the helical gear LSD will be the best compromise of minimal maintenance (vs clutches) and 'daily drivability' (vs lunchbox lockers).

It appears then that unless the M190 diff indeed has a bolted ring gear, that I will need to:

- replace the entire front differential. If I'm spending this cash, upgrading to the M210 seems the thing to do for the added capacity. New half-shafts may also be needed if the dimensions of M190 vs M210, or the capacities of the half shafts differ.
- get a new ring/pinion set for both front and rear diffs, presumably the 4.46 ratio used on the BD and BL's with AT, w/o Sasquatch. If a 4.27 WERE available for the M210, would this be suitable with the 33's and 10 spd AT (4.45% higher gearing than 4.46)? Would save having to open up the rear differential.
- pro installation required for any of these gearing possibilities.

I'm not weighing a Sasquatch or not decision for ordering here, rather laying out the possible ways to proceed in the future as Ford Performance or aftermarket components come to market.

Thanks in advance for your comments, corrections, or other insight as to the drive train modifications under consideration!

I believe you can just use an LSD with 3.73 like this:
https://www.4wheelparts.com/p/eaton...wn-rear-differential-913a589/_/R-BHXC-913A589
You would need to get a replacement ring gear for the LSD like this:
https://www.stage3motorsports.com/10062017-19-21-ranger-m220-rear-end-spicer-373-rear-gears.html

This is my preferred route. I just purchased my OBX without lockers. I doubt I will need them at all. I will be getting skid plates (ARB) soon just in case. If I see then that I need more traction I will get an LSD, but I don't think I really need to change gears since I plan on keeping 32s, and no bigger.

I didn't really have the choice (in Mexico there is only Badlands or OB with leather etc....) to choose a locker, so I think this is my best option. I really want a nicer daily driver not an offroader, and I think OB is still plenty capable.

 

[Rocketeer Rick]

I believe you can just use an LSD with 3.73 like this:
https://www.4wheelparts.com/p/eaton...wn-rear-differential-913a589/_/R-BHXC-913A589

FWIW, that specific LSD won't work here. That's for a "traditional" Dana 44, not the modern Advantec M220 axle sometimes called a Dana 44. But once somebody makes something that fits the M220 (if they haven't already), then your general principle will still hold. A diff made for the axle, paired with a ring & pinion set that's made to bolt to it, would still be a good solution for a lot of owners.

 

[wintoon]

FWIW, that specific LSD won't work here. That's for a "traditional" Dana 44, not the modern Advantec M220 axle sometimes called a Dana 44. But once somebody makes something that fits the M220 (if they haven't already), then your general principle will still hold. A diff made for the axle, paired with a ring & pinion set that's made to bolt to it, would still be a good solution for a lot of owners.

Thanks for the information. I have gone on one trail with my Bronco (OB without lockers) and it was pretty much unstoppable. Coming from Subaru this is a BIG upgrade for me. Even without lockers. I really think an LSD would be great for those of us who did not order lockers or prefer LSD.

If anyone figures out what model LSD and gears (and keep 3.73 gearing) to use I would appreciate it if you could send me a quick message!

 

[DReece65]

Has anyone looked at this option? https://www.stage3motorsports.com/rd245-19-22-ranger-arb-air-locker-locking-rear-differential.html
It is for the ranger M220 and you can get a replacement ring and pinion kit. It's also 32 spline for those of us with 3.73 ratio.

 

[DReece65]

I went to my local 4x4 shop and they want $3000 to do the ARB rear locker. Totally floored as I already have the compressor and KR mount. Looking for another shop or might have to try myself. Should have spent the $800

 

[AZ_Liberty]

Lack of a LSD is a pretty sad state of affairs. I live on a dirt road. My Mustang GT (factory limited-slip) will actually perform better than a Bronco in 2-hi in almost all circumstances. So will my son's crappy 2002 2WD Frontier.

Will definitely be looking for a way to add a limited slip to the 4.46 geared rear end.

 

[Montana Bronco]

Lack of a LSD is a pretty sad state of affairs. I live on a dirt road. My Mustang GT (factory limited-slip) will actually perform better than a Bronco in 2-hi in almost all circumstances. So will my son's crappy 2002 2WD Frontier.

Will definitely be looking for a way to add a limited slip to the 4.46 geared rear end.

Curious about your logic here. I’m not seeing how a 2WD vehicle, even with an LSD, will have better traction than a Bronco without lockers. I’m not seeing it.

 

[Hey Buddy]

How about this:
Bronco 2021 M220 Rear Axle Assembly 4.46 with Electronic ...
https://accessories.ford.com › products › bronco-m220-...





Fits 2021-2022 Bronco; Complete bolt-in rear axle housing; 4.46 ratio; Electronic locking differential; Axle shafts included; Brake rotors included ...
$2,485.00 · ‎In stock

I wonder if this could be swapped out on a base model & hooked to AUX switches?

 

[Mr. Snek]

That would be ideal if you could acquire the larger front differential with matching gears.

I think the problem breaks down into a few ways.
-Even if you want a locker for just the rear, purchasing a new ring and pinion is required as the R&P is laser welded from the factory.

-if you have an automatic aftermarket lockers may not play well with the trail turn assist if you activate it while locked.

-Purchasing both front and rear axles from Ford to get matching ratios may not be as plug and play as we think due to the base model not having the wiring routed for the electronics on the axles.

I've considered many options and I think what would be best for me and what I plan to do is get an rear air locker, air compressor, and regear my stock axles for my tire size (pending gears become available for the front diff). This will allow me to air up and down on the trails, and engage the lockers when I want to.

How about this:
Bronco 2021 M220 Rear Axle Assembly 4.46 with Electronic ...
https://accessories.ford.com › products › bronco-m220-...





Fits 2021-2022 Bronco; Complete bolt-in rear axle housing; 4.46 ratio; Electronic locking differential; Axle shafts included; Brake rotors included ...
$2,485.00 · ‎In stock

I wonder if this could be swapped out on a base model & hooked to AUX switches?

 

[KPLOBX]

Have no idea how much it would cost. I thought maybe just an electronic hookup would suffice without a big expense. I don't really want those big 35" tires or the lift that comes with it. If anything I would go to the Black Diamond package first.

I think that is your best bet. You’ll get more than you want but getting that stuff stock usually better value than mods.

 

[rodskies]

How about this:
Bronco 2021 M220 Rear Axle Assembly 4.46 with Electronic ...
https://accessories.ford.com › products › bronco-m220-...





Fits 2021-2022 Bronco; Complete bolt-in rear axle housing; 4.46 ratio; Electronic locking differential; Axle shafts included; Brake rotors included ...
$2,485.00 · ‎In stock

I wonder if this could be swapped out on a base model & hooked to AUX switches?

I wonder if the wire harness is already equipped with the control circuit for the solenoids for the sas lockers? Seems plausable since sas is just an opotion group on the base build, they could be using the same wire harness.... If so, might just be able to pop in a new control switch:

https://www.oemford.parts/oem-parts/ford-switch-assembly-m2dz13d730fa?c=bD01Jm49U2VhcmNoIFJlc3VsdHM=

I will check when my non-sas base gets in, if there are any plugs tucked away. Could be easier and the cost may be similar to just swap in the new axle than re-gear and install air.

 

[Hey Buddy]

I wonder if the wire harness is already equipped with the control circuit for the solenoids for the sas lockers? Seems plausable since sas is just an opotion group on the base build, they could be using the same wire harness.... If so, might just be able to pop in a new control switch:

https://www.oemford.parts/oem-parts/ford-switch-assembly-m2dz13d730fa?c=bD01Jm49U2VhcmNoIFJlc3VsdHM=

I will check when my non-sas base gets in, if there are any plugs tucked away. Could be easier and the cost may be similar to just swap in the new axle than re-gear and install air.

Let us know when you find out more?

 

[Hey Buddy]

Well, it appears that Yukon Gear is making a 32 spline e-locking rear differential for us & Eaton is offering a Trueloc LSD as well as a rear e-locker, just in 3.73 gear ratios, so far. I will remain patient & hope to do front & rear Eaton Trueloc LSD as soon as they let me know about them being available in a 4.46 gear ratio. I will keep you all posted as soon as I find out!

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