I recently bought a well-maintained 98 disco 1 auto. the cdl lever moves fine - shifts from hi to low with no issues and will shift side to side, BUT won't lock the diffs. i've taken the center console and boot out and can see the arms and lever work fine, rotating the switch, but no locking. I've made the adjustment from the top with an extended socket even. i even taken the nut and the arm off the switch to try moving it manually and still nothing. not just no light. i've jacked up the front wheel and there's definitely no locking. I've tried driving it forwards and backwards, but still no locking. I even changed the gear oil, and still no locking. I'm certain the switch is moving over enough, but whatever needs to happen inside the transfer case simply isn't happening.

Any thoughts? Should I open up the transfer case and have a look? Should I replace the switch on top?

Cheers.

 

Tell us more about your method of testing while you “jacked up the front wheel”.

The center diff simply splits power evenly to the front and rear. Your front differential and rear differential will still allow one of the wheels at each end of the truck to slip.

It absolutely does NOT make it so that every corner has power at all times.


These vids will help illustrate what goes on inside the diff.

 

I had the same issue thinking it did not engage. But the whole time it did. Found the wire was broken for the light. I took mine to a parking lot locked the CDL and drove slow and turned the wheel. Yep it worked just fine. Took about 5 feet to tell it was working. Don’t go fast of far with it locked on hard a surface.

 

As recommended on other posts, I basically jacked up one of the front wheels while truck was in both N and D and tried engaging the diff lock and then tried spinning the wheel and it would always spin. My understanding is that this would not be happening if the diff lock had engaged. I would also drive the truck around in circles on the bitumen with the lever engaged, hoping to feel the lurch the indicates the diff lock is engaged, but nothing there either.

I'm almost certain it is not engaging.

 

If only this had been the case for me - No, this is not happening on my truck.

 

When you lock your center diff lock it takes the power and splits it 50/50 front/rear. It will not keep one wheel from spinning on the front axle or rear axle. The only way you can achieve that would be putting locking diffs in each front and rear diff’s.

 

I'm not saying you're definitely wrong because I'm personally not absolutely certain how the mechanics of the assembly work - but you ARE definitely contradicting a whole heap of people who have said otherwise (with an obviously high degree of confidence).

"Is this how you tested the diff lock?

Definitive test. (Thanks to John JDNSW from a 2012 thread)

Handbrake on
Gearbox neutral (or T/C neutral)
Jack up one front wheel
With centre diff unlocked the jacked up wheel can be spun freely (well, relatively freely anyway) as the centre diff will operate as a differential, and the motion will spin the gearbox.
With centre diff locked, front wheel can only be turned a small part of a turn, as the front output shaft from the transfer case is now locked to the handbrake."

"With wheel jacked up and engaged, you shouldn't be able to turn wheel more than a few degrees(due to driveline slack)."

These are just two responses my post on another landrover board. I'm read the same thing countless other times.

But, in my case, even if that Is NOT the case, as stated, when the lever is in the engaged position, ,my turn radius is the same as always and I do not experience the lurching associated with turning on bitumen - so, I'm sure it's not engaging.

 

Diff lock solenoid. Remove the pin.

 

That test is 100% right. I missed the part about a one wheel on the ground. I was thinking you had both wheels up.

The down side of working 15hrs a day and reading on my phone.

im sorry for Leading you wrong.