Member Since: 17 Jan 2020
Location: England
Posts: 7
Diffs
I have a 2014 L494 HSE Dynamic SDV6.
Looking around online, I saw someone suggest that the Dynamics have the rear locking e-diff as well as having the standard centre diff.
Anyone know if that is true?
Fri Apr 03 2020 7:25am
Tim in Scotland
Member Since: 30 May 2005
Location: Driving along in my automobile
Posts: 17476
According to the sales brouchures I have 2014MY Dynamics (also Autobiography and 5.0lt S/C) No rear e-diff is listed even as an option, they all have the centre diff, but 2015 MY Dynamics show Rear e-diff and centre diff is standard. On pre-2015 HSE there was the option of an OnRoad/Offroad pack but even with that option no rear e-diff is fitted or optional. So if it’s any Dynamic Version after 2015MY (SD or S/C) will have the rear e-diff as standard2020 Pangea Green 1st Edition D240 New Defender 110 is here and loving it
2018 Melting Silver Mini Countryman PHEV - soon to be replaced
2015MY Corris Grey SDv6 HSE Dynamic, the best car I have ever owned, totally reliable only a cou0le of rattles in 3 years, now no longer in my care
Also in my garage is a 1996 TDi300 Defender 90 County HT made into a fake CSW
Fri Apr 03 2020 9:02am
naks
Member Since: 15 Jul 2016
Location: Stellenbosch
Posts: 1167
from the workshop manual for my MY15 RRS:
Open Differential
The open differential is a conventional design using a hypoid gear layout.
The aluminum casing comprises two parts; a cover and a carrier. The carrier provides locations for all the internal components. The cover is sealed to the carrier with Loctite RTV sealant and secured with bolts. The cover and carrier have cast fins, which assist rigidity and cooling. A breather cap is fitted to the top of the carrier.
The open differential contains a quantity of oil for splash lubrication of the internal components. A magnetic drain plug is
installed in the bottom of the carrier and a filler/level plug is installed in the cover.
The pinion shaft has an externally splined end which offers a direct connection to the driveshaft via the DTF (Direct Torque
Flow) connection. In comparison to the conventional flange connection the DTF connection provides:
- Reduced weight due to fewer components.
- Smaller outer diameter.
- Improved driveshaft imbalance.
- Reduced assembly time.
The pinion shaft has a hypoid gear at its inner end, which mates with the crown wheel drive gear. The crown wheel drive gear is located on the differential carrier and secured with bolts. The differential carrier is mounted on taper roller bearings located in machined bores in the carrier and the cover. Shims are installed behind the bearing cupsto apply the correct bearing preload and hypoid backlash.
The differential carrier has a through hole, which provides location for a cross shaft. The planet gears are installed on the cross shaft, with thrust washers between the planet gears and the differential carrier. A roll pin locks the cross shaft to the differential carrier.
The sun gears are located in pockets in the differential carrier and mesh with the planet gears. Belville washers are fitted between the sun gears and the differential carrier and set the correct mesh contact between the planet gears and the sun gears. Each sun gear has a machined bore with internal splines and a machined groove. The splines transfer drive to the rear drive halfshafts. The groove provides positive location for the snap ring fitted to the inboard end of the rear drive halfshafts. Oil seals are installed in the carrier and the cover to seal the rear drive halfshafts.
Electric Differential
The electric differential has the same functionality as the open differential, but it also incorporates a locking and torque biasing function to give improved traction performance and vehicle dynamic stability. Operation of the electric differential is controlled by the RDCM (Rear Differential Control Module).
The basic construction of the electric differential is similar to the open differential. However, the electric differential also has
the following:
- Two additional planet gears in the differential carrier, to cater for the higher torque through the differential during locking events.
- A multi-plate clutch and actuator assembly installed on the left-hand sun gear.
- A motor and reduction gearbox, attached to the cover.
- An oil temperature sensor installed in the cover.
The RDCM operates the motor of the electric differential under the control of the (ISCM) Integrated Suspension Control
Module.
The multi-plate clutch is contained in a clutch basket attached to the differential carrier with the crown wheel securing bolts. Alternate plates of the clutch pack are keyed to the clutch basket and the left-hand sun gear. A pressure disc is installed on the outer end of the clutch pack and keyed to the clutch basket. A thrust race on the end of the clutch basket incorporates lugs which extend through the clutch basket onto the pressure disc.
The actuator assembly is mounted on bearings on the outboard end of the clutch basket, against the thrust race. The actuator assembly consists of input and output actuators separated by five ball bearings. A locking pin in the cover engages with a slot in the output actuator to prevent it turning, but allow it to move axially. The input actuator engages with the reduction gearbox and is free to rotate relative to the cover. Ball bearings locate in curved grooves in the mating faces of the input and output actuators. The bottom surface of each groove incorporates a ramp. Rotation of the input actuator forces the ball bearings up the ramps in the grooves and induces an axial movement in the output actuator. The thrust race and pressure disc transfer the axial movement from the output actuator to the clutch pack.
The motor is a 12 V DC motor that adjusts the frictional loading of the multi-plate clutch, via the reduction gearbox and the actuator assembly, under the control of the RDCM. Adjusting the frictional loading of the multi-plate clutch adjusts the locking torque between the crown wheel drive gear and the sun wheel.
Four bolts attach the motor to the reduction gearbox, which is located in position on the cover with two dowels, and secured with four bolts. An O-ring seals the joint between the motor and the reduction gearbox.
The motor is driven by a 12 V DC feed direct from the RDCM. The motor also incorporates the following connections with the RDCM:
A motor temperature sensor, to prevent excessive use from damaging the motor.
Two Hall effect motor position sensors, to enable closed loop control of the motor.
The temperature sensor provides a differential oil temperature signal to the RDCM, to prevent excessive use from damaging the multi-plate clutch.
Rear Differential Control Module
The RDCM controls operation of the electric differential. The RDCM is attached to a bracket located on the right-hand side of the luggage compartment.
The RDCM receives three battery feeds from the RJB (Rear Junction Box) and an ignition feed from the CJB (Central Junction Box). A connection with the high-speed CAN (Controller Area Network) Powertrain bus allows the RDCM to communicate with other systems on the vehicle.
A certain amount of differential slip is required to allow the vehicle to turn corners and to remain stable under control of the ABS (Anti-Lock Brake System control module) . The ISCM monitors the driver's demands through primary vehicle controls and automatically sets the slip torque in the differential. The system is completely automatic and does not require any special driver input.
The differential strategy in the ISCM includes:
- A pre-loading function, increasing locking torque with increased driving torque.
-A slip controller to decrease locking torque for optimum comfort, for example when parking.
The ISCM memorizes the position of the motor when the ignition is switched off. CAN bus messages used by the ISCM include wheel speed, steering angle, automatic transmission speed, temperature information, car configuration, axle ratios and mode inputs.
The ISCM also sends messages via the high speed CAN Powertrain and Chassis bus to tell other control modules on the network the status of the electric differential. The clutch torque and default mode status are some of the main signals sent out by the ISCM.
OPERATION Open Differential
Rotational input from the drive shaft is passed via the input flange to the pinion shaft and pinion gear. The angles of the pinion gear to the crown wheel drive gear moves the rotational direction through 90°.
The transferred rotational motion is now passed to the crown wheel drive gear, which in turn rotates the differential casing. The cross-shaft, which is secured to the casing, also rotates at the same speed as the casing. The planet gears, which are mounted on the shaft, also rotate with the casing. In turn, the planet gears transfer their rotational motion to the left and right hand sun gears, rotating the drive halfshafts.
When the vehicle is moving in a forward direction, the torque applied through the differential to each sun gear is equal. In this condition both drive halfshafts rotate at the same speed and the planet gears do not rotate.
If the vehicle is turning, the outer wheel will be forced to rotate faster than the inner wheel by having a greater distance to travel. The differential senses the torque difference between the sun gears. The planet gears rotate on their axes to allow
the outer wheel to rotate faster than the inner one.
Electric Differential
The multi-plate clutch prevents excessive differential slip and therefore maximizes the traction performance of the vehicle. This is fundamentally different from 'braked' traction control systems, which can only counteract differential slip when it occurs.
A certain amount of differential slip is required to allow the vehicle to turn corners and to remain stable under control of the ABS. The system is completely automatic and does not require any special driver input.
The multi-plate clutch actively controls the torque flow through the differential and optimizes the torque distribution in the driveline. The clutch biases the torque from the differential to the wheel with the higher grip and prevents the wheel with the lower grip from spinning.--
2010 Defender Puma 90 + BAS remap + Alive IC + Slickshift + Ashcroft ATB rear
2015 Range Rover Sport Supercharged V8 HSE Dynamic
Member Since: 06 Apr 2014
Location: Windsor
Posts: 15
I had a 2014 Sport HSE Dynamic (now replaced with P400e) this has fitted as standard the rear locking differential (with low range box, TR2) and the other Dynamic bits and pieces. The HSE [non dynamic] did not as standard - only with the 'off-road pack which included the fancy suspension low range box and locking rear diff.
The way to check is to show the 4x4 Info on the screen - a visual of drievtrain and suspension and if you have the locking read diff you will see two locking symbols on the screen, on in the centre and one a t the back. Non rear lock cars only have one i the middle.
These days the Dynamic spec seems to be is more about the look than the drive train (except for the Hybrid P400e where it is also standard)
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Fri Apr 03 2020 9:02am
