How does Quadra Drive II work?

[multihull]

My diffs have always locked in Low Range (may be it’s just the front because I’m on full lock or close to it) I thought this is part of the standard operation of the Commander system as it's always been this way but i've been told I may need to change my diff fluid. The diffs don't lock completely but have a different action to when in HR. It's only noticeable on hard lock and when you drive onto more stable hard ground or when manoeuvring in some tight 4WD applications. Why doesn't it happen in High Range?

How do all the other electronic systems interact and affect Quadra Drive II

How do the hydraulic diffs respond and act and what happens to the transfer case clutch system?

There’s a lack of info in the manual on how this whole system works and integrates, can someone add more light on the subject? I have down loaded info from the web but there’s still a very grey area.

Don't get me wrong I don't have a problem with my Commanders off road ability, it's awesome and I take her up and over some really extreme stuff, terrain the stock or slightly modified Pajeros, Patrols and Cruises opt out off. I'm just puzzled on how it all works.

[08crd]

From memory the centre diff has a georotor pump working in conjunction with electronic speed sensors. In high range under normal driving conditions 52% of drive is sent to the rear axle 48% to the front. If the electronics sense a difference in speed the georotor oil pump loads up the clutch packs progressively . In low range the centre diff is automatically locked i.e the clutch packs are loaded. The front and rear diffs also have a similar georotor pump and clutch pack assembly and can theoretically direct drive to either both or one wheel depending on which is not spinning. Which in theory makes it one of the only true 4 wheel drives around. Most use l.s.d or traction control on the wheel braking system, the problem with this is it robs the engine of power by applying the brakes and slowing the vehicle down. Anyway thats my understanding of it in a simplistic way.

[Jeeptheone]

Watch and enjoy

http://www.jeep.com/en/4x4/how_syste...uadra_drive_2/

JTO

[08crd]

Excellent demonstration. Thanks for that.

[Bomber]

That used to be on the Aussie site too (not sure why they'd take it down ) but it only explains what it does not how it does it.

The XH QDII (and WH if QDII) has ELSDs at front and rear and centre.

QDII uses Eaton's EGerodisc™. I found the following at jeepcommander.com a while ago.

EGerodisc™ is a hydraulically-operated electronically controlled limited slip differential that is capable of providing variable torque up to full axle lock, helping to maximize traction when needed. The EGerodisc™ can be used as a stand-alone product that provides ultimate traction control, or it can be integrated with ABS or stability control packages to also provide enhanced vehicle dynamics. Be sure to ask your dealer if your vehicle has an Eaton differential.

A gerotor pump (1) creates oil flow through the filter (4) whenever left and right wheels spin at different speeds and the solenoid valve is activated. The oil flow is restricted by a Pressure Regulating Valve (PRV) to build oil pressure. Pressurized oil is then fed to a piston (2) chamber. The piston compresses the clutch pack (3) providing additional torque to the lower speed wheel.

When the antilock brakes are activated the differential solenoid is switched off and pressure is bleed off the clutch pack

[TOYROX]

In high range the system operates and will split the drive dependent on wheel slip. In low range the drive to front and rear diffs is locked in the transfer case. Thats why it feels different.

[multihull]

Originally Posted by TOYROX

In high range the system operates and will split the drive dependent on wheel slip. In low range the drive to front and rear diffs is locked in the transfer case. Thats why it feels different.

Another question, So why does the system need electronic brake traction control in H/R as well when it already has this hydraulic clutch system?