Thread: Cannot disengage CDL. What to do?

Originally Posted by frankdisco

After countless effort to put it back to normal 4H, we proceeded with removing the battery. This did not work as the light was still on. Then we decided to jack the D1 and spin the front wheel to really check if locks are still engaged, and yes they were..

I have more trouble getting the box to move from 4L back to 4H. In this case reversing is still the answer, maybe quite a few metres - with hand on the lever with firm force, but don't overdo the pressure as the linkages are fairly basic. I generally have less trouble engaging/disengaging the diff lock.

Regardless of which issue. Be aware if you have loaded the system with stress on a hard packed surface and you are applying hand force, you may find when the system finally disengages it may do so with a bit of a 'bang' ASAP rather than waiting to be in a 'fully relaxed' state for a quiet disengagement.

Note 4 High and 4 Low operate independently of the centre diff lock. The light is just there to tell you that the diff lock is on or off and has no role at all in manipulating the centre diff, or for that matter the 4H/4L. You won't need a light to tell you that you are still in 4L because you just won't go anywhere fast. It's a different situation with the centre diff because you need to know it is on when the surface is loose, and off when you are back on paved road.

Don't know your previous 4x4 experience so apologise if the following is telling you how to suck eggs. Imagine you are on a track with potential for wheel lift. Your centre diff is not locked. The moment any 1 of your 4 wheels lifts then forward progress stops. The centre diff is locked to split the power 50/50 between the front drive shaft and rear drive shaft to give you twice the chance of forward progress. Now locked, you will require one rear wheel and one front wheel to lift at the same time to stop progress. Off course if you have a lockable centre diff and lockable front and rear diffs then all your wheels would have to be off the ground to stop you - one wheel with good traction will keep you going, in theory.

There is another reason for locking the centre diff. It is to safeguard the diff, removing some stress from the gears and the small shafts they rotate on.

Originally Posted by V8Ian

Note, if the lever hasn't been moved regularly/lately it can be very stiff.

Indeed.

the easy test for CDL engaged or not.

assuming you dont also have a locking or torque biasing diff in the front.

park brake on, Gearbox and T canse in neutral and jack up a front wheel.

try to turn the front wheel. IF it turns CDL is out if it doesnt its stuck...

assuming its not a stuck selector linkage or shift lever mechanism, agressively roatate the front wheel by hand bouncing it from clock wise to anti clock wise off of the transmission wind up.

In severe cases you will need to jack up one front and one rear tyre and do this with the park brake disengaged. If you need to do this more than occasionally, you have an underlying driveline issue that needs to be looked at.

Good luck

I have had the issue of won’t lock or unlock in mine if it wasn’t used for a while
on occasions I have got out of the car and pulled very hard with both hands to get it to lock
Jack up both front wheels and try with both off the ground, check the linkages under the car and spray a heap of Wd40 on them, as said reverse back and forth while putting a fair amount of pressure on the lever.
you could also try going from high to low a few times, this must be done in neutral of course but it will get everything moving and free it all up if it hasn’t been used in a long time
once the lever comes across the light may take a little while to go out

Jeez talk about internet misinformation.
DO NOT jack up both front wheels,Just one. If you jack up both and turn one the other wheel will turn in the opposite direction and the driveshaft will not turn.
The transmission will need to be in Neutral or the driveshaft will not turn . If you have "wind Up" the whell you jack up will turn a bit as it comes off the ground. Do not drive a long way with diff lock or bye bye universals.
Usually if someone is in the car jerking on the lever it will disengage. I would also be looking at the oil level in the transfer case as the diff lock is disengaged by a spring inside the case Pushing a shaft backwards.
Some wd40 or similar sprayed on the linkages should help. AFAIR the D1 has rods. The D2 has cables.
Regards PhilipA

Not internet misinformation, if you jack up both wheels it releases all potential windup from the drive train, IF it is windup jack up one wheel and it will just release the tension, it it’s a mechanical cause having no weight on the front axle will allow you to play with the linkages under the car and also get a bit of movement in the driveshaft

Originally Posted by discomatt69

Not internet misinformation, if you jack up both wheels it releases all potential windup from the drive train, IF it is windup jack up one wheel and it will just release the tension, it it’s a mechanical cause having no weight on the front axle will allow you to play with the linkages under the car and also get a bit of movement in the driveshaft

you what now? this is an explination I need to hear

The owner of the Dealership I bought it to has just called me an ask to bring it back to their shop to get it fixed. I believe he has some contacts who's familiar with the situation. Will be updating soon. Thank you everyone for your inputs! I appreciate every response. You all have a pleasant weekend and enjoy the sun!