[svxistentialist]

Originally Posted by Zandar

I've been looking through the forums and I see rumours of this but no real information.

Is there a mod that locks the car in 4WD (i.e. 50/50) mode? What would it take to do this? What are the pros and cons?

Just curious.

What Tom said. I agree with his pros and cons. Further, I suspect you could actually do this [lock the centre differential] and drive on very loose gravel, or soft muck or in snow/sheet ice. There would not be high grip, so lower torque loads applied to the centre diff. It could be useful for "rocking" the car out of a stuck position.

On our VTD cars putting in the fuse locks this diff and the warning light comes on on the left upper dash position. I'll give you verbatim what the RHD owner manual says about this:
Section 3.10

Centre Diff Lock Warning Light:
This warning light comes on when a fuse has been inserted in the DIFF LOCK socket in the engine compartment, which is done to put the vehicle into the locked central differential drive mode during maintenance and service. For everyday operation the fuse should be removed from the DIFF LOCK socket and therefore, this light will not normally be on.


And from Section 10.4:

NOTE:
When tests with a brake tester or chassis dynanometer, such as braking force tests or speedometer tests, it is necessary to put a spare fuse [10A/15A] in the DIFF LOCK socket located at the fuse box in the engine compartment.
Confirm that the DIFF LOCK warning light comes on.


This second note is accompanied by a diagram showing the car with front wheels on a dyno roller, and the rear wheels either on jack stands [to spin freely] or on what is described as a free roller.

This probably indicates that the design function in both cases is to facilitate this dyno testing.

In the case of the US gearbox fitting the fuse disengages the centre differential from driving the rears [electrically, by disengaging the rear drive solenoid].

In the case of the VTD type, the fuse locks the centre diff 50/50, but the testing is done with the rear wheels spinning freely.

Joe