RWD, or FWD in a RRS/D3

The TR responds to wheel speeds, not shaft speeds, and of course it reacts via two pathways - the (lockable) diff(s), and the braking system. I had a fleeting idea of tricking a wheel speed sensor, before realising that not only would the CDL actuate, but so would the brakes :(

My experience with driving a D3 with a non-functioning CV joint was that once the car was moving, it would putter along in R/C (in Command Shift) as long as there were no sharp corners, for which you were relegated to coasting around. Once moving at a reasonable speed, you could change up to high-range + Mud-Ruts. Getting it to move in the first place was the issue!

With a diff gone, I don't know that the experience would be the same.

Cheers,

Gordon

Just had another thought, could the cdl be locked with a Nanaocom, Faultmate, etc even in High Range? Also perhaps the the T.C. disabled or diminished as well, and/or disable or diminish rear wheel braking ?

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Originally Posted by gghaggis

The TR responds to wheel speeds, not shaft speeds, and of course it reacts via two pathways - the (lockable) diff(s), and the braking system. I had a fleeting idea of tricking a wheel speed sensor, before realising that not only would the CDL actuate, but so would the brakes :(

My experience with driving a D3 with a non-functioning CV joint was that once the car was moving, it would putter along in R/C (in Command Shift) as long as there were no sharp corners, for which you were relegated to coasting around. Once moving at a reasonable speed, you could change up to high-range + Mud-Ruts. Getting it to move in the first place was the issue!

With a diff gone, I don't know that the experience would be the same.

Cheers,

Gordon

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Thanks Gordon - I must admit, that is what I was sort of thinking before putting up the thread. However I was hoping I was sort of missing something.

It would be nice if there was a manual cdl lock button in the system somewhere - even if there was an annoying alarm etc so that you would not do it unless you really needed to.

Cheers

Garry

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Originally Posted by RANDLOVER

Just had another thought, could the cdl be locked with a Nanaocom, Faultmate, etc even in High Range?

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I intend seeing if Faultmate can provide anything, perhaps along the lines of it being able to put the suspension ecu into diagnostic mode and operate the valves individually.

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Originally Posted by Graeme

I intend seeing if Faultmate can provide anything, perhaps along the lines of it being able to put the suspension ecu into diagnostic mode and operate the valves individually.

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According to Colin it can, although I've never had a close enough look - might try this weekend.

[Oops - meant that it can do the EAS diagnostics - don't know about the centre diff!]

Cheers,

Gordon

No test or calibration options exist on my Faultmate for either the centre diff or the rear e-diff. I had hoped to be able to recalibrate the motor in the e-diff in the event of having to replace the motor but that's not possible atm at least.

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Originally Posted by gghaggis

My experience with driving a D3 with a non-functioning CV joint was that once the car was moving, it would putter along in R/C (in Command Shift) as long as there were no sharp corners, for which you were relegated to coasting around. Once moving at a reasonable speed, you could change up to high-range + Mud-Ruts. Getting it to move in the first place was the issue!

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This doesn't sound too bad noting that at best its only 2WD.
As the wires for the lock motor are in the main connector that includes the can-in and can-out bus wires, unplugging the ecu to prevent control of the lock motor would cause a whole lot of other problems and likely to include limp mode for the gbox so is not really an option. A connector that plugs a special control unit into the lock motor instead of the harness from the ecu could be useful. Perhaps the lock motor harness needs to be unplugged to see what that triggers - maybe a task for tomorrow.

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Originally Posted by gghaggis

- might try this weekend.

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Originally Posted by Graeme

- maybe a task for tomorrow.

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I eagerly await your reports ;).

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Originally Posted by gghaggis

We discussed this 4 or 5 years ago - I had asked some of the LR techs if it was possible to fabricate an electronic switch to lock the diff if something like this occurred. The considered opinion was that the diff is not designed to be permanently locked, so would result in damage to the motor.

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I see that the e-diff is also fitted with an actuator brake solenoid. The combination of the techs' opinions and the e-diff's actuator having a brake leads me to suspect the centre diff's actuator motor needs to be powered to keep pressure on the clutch plates so would overheat if operated for too long. The motors are fitted with temperature sensors which adds support to the logic.

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Originally Posted by Graeme

I see that the e-diff is also fitted with an actuator brake solenoid. The combination of the techs' opinions and the e-diff's actuator having a brake leads me to suspect the centre diff's actuator motor needs to be powered to keep pressure on the clutch plates so would overheat if operated for too long. The motors are fitted with temperature sensors which adds support to the logic.

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That was the gist of it - I was looking at a setup that would be controlled by a non-latching momentary on switch so that the driver would have to keep the button pressed to lock - enough to get rolling and around corners.

Cheers,

Gordon