Thread: rear e-diff

Oh dear - you really need to a lot of research before embarking on such a project - even basic research would have shown whats in the diff housing is vastly different between the open and ediffs - not friction plates in the open diff - heaps of friction plates in an e diff.

This is the e-diff of a D3 - you can see the plates and the motor and this will be basically the same for a later RRS.


LR3 Rear Locker cut showing Stepper Motor and disc plates big 10.jpg

Did you review the link I put up earlier on the experiences of someone actually doing it in a D4?

Originally Posted by 101RRS

Did you review the link I put up earlier on the experiences of someone actually doing it in a D4?

I did, saw it, understood parts of it, but undeterred so I’m pressing on.
If I learn a bit along the way then that’s the fun of it.
Apologies upfront if I’m wasting you time.

My concern is that you'll start buying parts then not complete the task.

Here's my retrofit thread.

Rear e-diff retrofit to MY12 4.4 TDV8

Yes that is my concern - was already looking at buying parts from different models that may not fit and not even understanding the physical differences between normal and e diffs (ie assuming the friction plates are in the open diff and only need the motor).

Now I think this is a worthwhile project if you are so inclined but a lot of research and learning of the systems are needed before even going out and looking for parts.

I accept that coming here and posing questions is a great way to start the research process but hasten slowly comes to mind.

Now I dont know - but before I embark on the e-diff route, I would be checking to see if the D3 front and rear diffs fit in your much later vehicle as ARB diff locks will fit. Also, I would look at whether you really need your ediff linked into your car's systems - the motor just changes the amount of friction at the plates so manually applied voltages may be able to be applied to the diff motor - so if you apply the unlocked voltage to the motor, does the diff go unlocked, same with a mid range voltage and the same at the fully locked voltage - does it actually lock the diff?

I don't know but would seem a simpler solution that a complex fully integrated solution. There are options.

Garry

Sourcing the correct ratio diff is the biggest hurdle, with the other aspects rather trivial although one must fit an appropriate control module for the vehicle. Integrating with the rest of the electronics is the least of concerns because the other modules already allow for an e-diff if the CCF shows that one is fitted.

The L405/L494 diff housing is quite different to the D3/D4/L320 housings and both early and later L322 housings.

Originally Posted by Graeme

Sourcing the correct ratio diff is the biggest hurdle, with the other aspects rather trivial although one must fit an appropriate control module for the vehicle. Integrating with the rest of the electronics is the least of concerns because the other modules already allow for an e-diff if the CCF shows that one is fitted.

The L405/L494 diff housing is quite different to the D3/D4/L320 housings and both early and later L322 housings.

Thanks Gents, Haven't bought anything and I will continue research.

My plan currently is to look for a MY16 SDV6 or TDV6 'REAR AXLE ACT LCKG DIFF W/TVBB' to Replace my 'REAR AXLE OPEN DIFF' and hopefully from that L494 grab the ediff ECU and cabling harness.

Have yet to find one of these rare beasts but I did find a MY14 L494 with what I needed.

Regards

With much research I've been chasing the following part numbers for the rear locking diff (REAR AXLE ACT LCKG DIFF W/TVB;

LR070145 or DPLA4A213FC which have a diff ratio of 3.21:1

The RDCM ( Rear Differential Control module ) ediff module or ECU is required also which links into the ISCM Integrated Suspension Control Module which controls the Air Lift and Continuous Variable Damping which I already have.

See attachments more info.

the Rear diff rations are;

Reduction ratio:
Vehicles with 4.4L diesel engine	2.73:1
Vehicles with 3.0L diesel engine	3.21:1
Vehicles with 5.0L supercharged petrol engine	3.31:1
Vehicles with 3.0L supercharged petrol engine	3.73:1
Vehicles with 3.0L diesel hybrid engine	3.21:1

If buying a reconditioned diff, you need to check if the diff motor is included. LR changed from allocating a number to the diff including the motor to a different part number for the bare diff, ie without the motor. LR070145 supersedes an earlier number so technically might not include the motor, but would expect to if sourcing from a wreck.

Have you identified the RDCU part number for MY14+ RRS / L405?

A friend has recently bought a MY14 RRS fitted with the Dynamic Pack which includes the e-diff for "torque vectoring" which therefore should be compatible with your MY16.