Quadra-Drive II is Really Just Quadra-Trac II + Rear eLSD

[GC_chief]

The Jeep GCL Build & Price Tool doesn’t appear to call out the Quadra-Drive II option separately, which is somewhat confusing. I believe the Quadra-Trac II and Electric LSD options combine to form what is called QDII. Can anyone confirm this?

From FCA:
The Quadra-Trac II's two-speed active transfer case with low-range gear reduction uses input from multiple sensors in the vehicle to pre-emptively adjust torque distribution and will continue to reactively make corrections if tire slip occurs. When wheel slippage is detected, as much as 100 percent of available torque is instantly routed to the axle with the most traction. Active 4-Low torque control with 2.72:1 gear ratio improves off-road maneuverability and delivers uncompromised performance.

Quadra-Drive II, with a two-speed active transfer case and rear eLSD, delivers industry-leading tractive capability. The system instantly detects tire slip and smoothly reacts distributing engine torque to tires with traction. In some cases, the vehicle will anticipate low traction and pre-emptively adjust in order to limit or eliminate tire slip. Quadra-Drive II is available on the Overland 4x4 model when equipped with the Off-Road Group and standard on Summit models.

 

[canesice]

I found this article which offers some details: https://www.motortrend.com/news/2021-jeep-grand-cherokee-l-four-wheel-drive-system-differences/

 

[GC_chief]

I found this article which offers some details: https://www.motortrend.com/news/2021-jeep-grand-cherokee-l-four-wheel-drive-system-differences/

Thanks, yeah I’ve seen those articles too. The issue is that “Quadra-Drive” appears to be a nickname or marketing term, not an actual standard feature or option you can see or select on the build sheet. On the Summit you see two standard features - Quadra-Trac II and eLSD, and on the Overland you have to get the off/road package to add eLSD. Neither model lists “Quadra-Drive” in the standard or optional features.

 

[Sarge]

What I'm trying to figure out is how difficult it would be to add a 'dumb' LSD or a separately wired e-locker to an Overland (or other model) that doesn't have a factory eLSD.

 

[Jim1234664]

correct, QDII is QTII with the ELSD. Keep in mind the elsd includes a lot of programming changes as well as the actual unit.

 

[Sarge]

correct, QDII is QTII with the ELSD. Keep in mind the elsd includes a lot of programming changes as well as the actual unit.

I'm sure it does. That's why I was thinking maybe just adding a Detroit Locker or some other mechanical unit (if available) would work, and just go unnoticed by the electronics. I would still give an edge over the brake-based system, and the factory electronic unit is still just LSD (not a full locker) as I understand)

 

[Jim1234664]

I'm sure it does. That's why I was thinking maybe just adding a Detroit Locker or some other mechanical unit (if available) would work, and just go unnoticed by the electronics. I would still give an edge over the brake-based system, and the factory electronic unit is still just LSD (not a full locker) as I understand)

Hopefully that would work. I think there is some chance that the brake system would brake the spinning wheel before the locker really has a chance to lock. I guess you could just power through it if that were the case.

The lsd is actually pretty slick. It can be a full locker or anywhere in between. I have it on mine and haven't seen a whole lot of snow yet. I will say it locks enough to chirp the tires doing a tight low speed turn.

 

[freethinked]

> The lsd is actually pretty slick. It can be a full locker or anywhere in between

Do you have any specs on the part? I'm still trying to understand the design of the system (just studying differentials for fun).

 

[Jim1234664]

> The lsd is actually pretty slick. It can be a full locker or anywhere in between

Do you have any specs on the part? I'm still trying to understand the design of the system (just studying differentials for fun).

The Smarter Way to More Grip

The eLSD electromechanical locking differential maintains thrust in extreme situations. This new networked solution brings many other advantages along with it.

www.zf.com

 

[freethinked]

Found a good tear down of the part. This is the older version of the eLSD but the part looks the same outside the control module.

230mm Differential - Tear Down

www.jeepgarage.org

 

[Jim1234664]

Found a good tear down of the part. This is the older version of the eLSD but the part looks the same outside the control module.

230mm Differential - Tear Down

www.jeepgarage.org

Good read, thanks for posting it.

We got a little snow today and I hit the gas a bit more than usual from a stop with the wheel turned. It was a little violent and felt a lot like a locker or spool. I Think the stock ELSD programming is pretty aggressive about how much of a lock it gives you.

 

[Sarge]

Found a good tear down of the part. This is the older version of the eLSD but the part looks the same outside the control module.

230mm Differential - Tear Down

www.jeepgarage.org

Interesting. So if you want to oversteer (i.e. for fun in the snow), the eLSD will work to prevent it, rather than help create it.

From the link:

In addition to interventions to provide a reaction to events, predictive pilot control strategies can also be implemented. "This provides more traction and prevents oversteering."

Ergo the OEM ZF eLSD might be better for safety, and good for rough terrain, but if you want to slide around in the snow on purpose, you're better off with something else entirely. Reading this article, it seems like maybe an Eaton TrueTrac might be best for WL use, where outright 'rock crawling' isn't part of the equation, but you want improved traction in mud, snow, etc.. Going above that, the Auburn ECTED offers sort of a combination LSD with a 12V locking option. If it wouldn't interfere with the programming of the stock system, the latter might be the most off-road worthy option.

IIRC my old Wrangler Rubicon LJ had a rear LSD that was also (definitely) electrically lockable. The ECTED diff sounds similar to that. I'm not sure who makes gear that fits with the WL, but it would be nice to have some options.

 

[nealtrombley]

195MM Front Axle Quadra-Trac II (R) 4WD System 3.45 Rear Axle Ratio Conv Diff Frt Axle w/Disconnect Conventional Differential Rear Axle Normal Duty Suspension Quadra-Lift (TM) Air Suspension

my build sheet, 21 Summit Reserve V8 so yes or no for me on the Elsd

 

[Jim1234664]

No elsd (conventional differential). As far as I know no V8s got them. The only SR's that have it are early v6s. I don't think they made any v8s in the first run. Mine was built in June and I got it. Bought early August but even then the forums said it was being deleted on newer builds.

 

[Sarge]

No elsd (conventional differential). As far as I know no V8s got them. The only SR's that have it are early v6s. I don't think they made any v8s in the first run. Mine was built in June and I got it. Bought early August but even then the forums said it was being deleted on newer builds.

You would only have the eLSD on either the V8 or V6 Overland trim (or below) if you ordered the Off Road Group package (which gets you 18" wheels vs 20"), UNLESS you got a 4x4 Summit or Summit Reserve, in which case the eLSD is standard. I could be wrong, but that was my understanding.

 

[Jim1234664]

You would only have the eLSD on either the V8 or V6 Overland trim (or below) if you ordered the Off Road Group package (which gets you 18" wheels vs 20"), UNLESS you got a 4x4 Summit or Summit Reserve, in which case the eLSD is standard. I could be wrong, but that was my understanding.

That is correct. I believe at this time though that not a single off road package overland has been produced. Both summits and reserves have seen the elsd deleted in all but some of the initial units.

Of course, this is an amalgam of information I have gleaned from the forums. There may be more to the story in reality. Also, they may begin shipping 2022s without the ELSD delete at some point.