Testing operation of rear differential lock?
Discussion
My VW Touareg has a manually lockable rear differential. However, whilst offroading at the weekend I noticed that when I manually locked it the display on the dash was not illuminating, leading me to wonder if the diff lock was bust.
Is there a way to test whether the rear diff lock is working?
Don't know if relevant but the car also has a manually lockable centre diff (which seems to work fine according to the dash display). The manual locking can only be perfomed when low ratio is selected. The centre and rear diff locks operate automatically when in high/normal ratio.
Thanks.
Is there a way to test whether the rear diff lock is working?
Don't know if relevant but the car also has a manually lockable centre diff (which seems to work fine according to the dash display). The manual locking can only be perfomed when low ratio is selected. The centre and rear diff locks operate automatically when in high/normal ratio.
Thanks.
If the rear diff is locked, simply drive around on a grippy surface in a tight circle.
The driver should be able to tell, and if not, someone outside should be able to see the fact that its locked, not allowing the rear wheels to turn at different speeds, as the tyres wil be trying to fight the rotation.
The driver should be able to tell, and if not, someone outside should be able to see the fact that its locked, not allowing the rear wheels to turn at different speeds, as the tyres wil be trying to fight the rotation.
leorest said:
I presume that if you compare the marks left in gravel when you drive in a tight circle with diff lock and off then you should see a noticeable difference without unduly stressing anything.
Good thinking, it'll be like Torvill & Dean carving patterns in the ice.If the rear diff is successfully locked then the rear tyres should leave bigger drag marks in the gravel compared to when the diff is open.
I'll take it very easy. The rear diff can only be manually locked when low ratio is engaged and the centre diff has also been manually locked, so this means the amount of torque going through the components will be very high. Cheers.
Edited by Hereward on Wednesday 11th March 16:22
The Excession said:
I'd also like to add that anyone who drives a vehicle with the rear diff locked and doesn't notice really shouldn't be
Helpful. I wasn't driving around with the diffs locked - I chose to manually lock the diffs about three times for less than 10 seconds each time, when approaching terrain where I knew one wheel would be off the ground. I glanced at the dash and noticed the rear diff lock symbol handn't illuminated.- driving that type of vehicle
- fiddling with a rear diff lock switch
Hereward said:
However, whilst offroading at the weekend I noticed that when I manually locked it the display on the dash was not illuminating, leading me to wonder if the diff lock was bust.
Hereward said:
The Excession said:
I'd also like to add that anyone who drives a vehicle with the rear diff locked and doesn't notice really shouldn't be
Helpful. I wasn't driving around with the diffs locked - I chose to manually lock the diffs about three times for less than 10 seconds each time, when approaching terrain where I knew one wheel would be off the ground. I glanced at the dash and noticed the rear diff lock symbol handn't illuminated.- driving that type of vehicle
- fiddling with a rear diff lock switch
My advice would be try locking the diff before you need it and checking how long it takes to engage etc. You know - get to know your vehicle.
My point still stands, anyone that can't tell that they are running with a rear diff locked is out of their league in that vehicle.
Seriuosly, how can you not know if the rears are diff locked??? If you've got a wheel off the ground then you simply have no drive on the other rear or you can feel/see that the grounded wheel is working.
As for the dash, it means nothing more than whether the bulb works or not, you should be able to feel/hear/sense whether the diff is behaving as you intend it.
Jack up your rear end both wheels off the ground.
Turn wheel the otherside will go the opersite way when the its a normal diff. Engage the diff lock and both wheels will turn the same way.
You may need to remove your prop at the diff to check this tho.
Its not the best idea to drive in circles with the diff locked especially not on high grip surface it doesnt take much to damage the diffs when they are locked up.
Turn wheel the otherside will go the opersite way when the its a normal diff. Engage the diff lock and both wheels will turn the same way.
You may need to remove your prop at the diff to check this tho.
Its not the best idea to drive in circles with the diff locked especially not on high grip surface it doesnt take much to damage the diffs when they are locked up.
To close this riveting story:
I drove tight circles in a gravel car park and it was obvious the centre diff was locking but not the rear diff.
Took it to VW. They diagnosed that a low voltage at some point had deactivated the rear axle electronic diff lock "brain" so the locking function (both automatic and manual) on that axle had been disabled. They cleared the fault, reset the brain, washed and vacuumed the car and charged me absolutely nothing. Great result.
I drove tight circles in a gravel car park and it was obvious the centre diff was locking but not the rear diff.
Took it to VW. They diagnosed that a low voltage at some point had deactivated the rear axle electronic diff lock "brain" so the locking function (both automatic and manual) on that axle had been disabled. They cleared the fault, reset the brain, washed and vacuumed the car and charged me absolutely nothing. Great result.
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