To make a short story long.....

We had a lot of snow on Friday which made me happy to finally put the Disco and it's locking central diff to the test...

I threw the beast into Lock mode (high) when I left the office and drove her home. I didnt notice anything different in the ride in deep snow and as for as long as I had the truck, the diff-lock light never came on, so I figured it was just burnt out. I have not driven the disco since, but I went to work this morning as usual.

During the day, I wondered if I had unlocked the diff. So I made a mental note to do it when I left. I shifted out of High mode, then hard to the right and down. I got to my first stop light and when I took off, the central lock popped out of gear. I panicked and tried jamming it into gear, but it grinded. I dropped to neutral and jammed it into gear and then threw it in drive. This is when I noticed that the Diff-Lock light was now on!

I pulled over in the parking lot and tried taking it out of gear and back etc to no avail. Driving forwards, then backwards. I talked to Land Rover Support (e.k.a. FishEH) and the best that we can determine (and hope) is that it is stuck in lock mode.

I limped it home and parked it....

I am not sure where to go from here except to pull the boot and see if I can jam the shifter over far enough to disengage the lock. If that doesnt work, I will have to try and get under it and disengage it manually.

Suggestions from anyone who had this problem would be helpful I am keeping my fingers crossed that this problem is related to the shift linkage and not the T-case.

 

When I bought my 94 the CDL light was on and wouldn't go out. I climbed under and manually rotated the shifter and it's worked well ever since. At least the light seems to correspond with CDL anyway.

I ended up using a screwdriver to get a bit of leverage and rotate the shifter plate. I've read about some people using a properly sized socket or wrench to manually turn the nut that holds the shifter cam in place. Good luck!

 

To lock the diff all you do is slide the lever to the left, weather in high or low, it should slide easily, you only need to put the transmission in neutral to switch between high and low.

 

I am almost relieved to hear this because there is obviously something wrong with my linkage because it never worked that way. I have always had to do the standard "H" pattern; pop it out to N and then over and down. It appears to me now that it isn't stuck inlock mode, the linkage is messed up and cant shift.

Anyone have a linkage for sale?

 

Essentially there are 9 positions on the CDL shifter ****.
3 o o
o o o
2 o 1
This is the basic pattern. The numbered positions are really the only ones you'll need. I've never had my Transfer Case on LO when the CDL wasn't locked, nor had the need to do so.
Position 1: HI, CDL unlocked(normal driving)
Position 2: HI, CDL locked
Position 3: LO, CDL locked

From position 1 you should be able to move directly to position 2. This should be one smooth move, though occasionally I've had to put the Transmission in N, then back in drive to complete locking the CDL. From position 2 you should be able to move the lever straight forward to position 3. Again it should be one smooth move but I've had to cylce the transmission to N and back to D sometimes to complete putting it in LO.
I always make the "L" pattern when using my CDL. You could make any pattern you want really, its just extra steps and more potential to get confused as to what position you're in I feel.
Pulling the center cousel isn't too bad a job. Its just a bunch of screws and nuts. Pull it out and see what's going on down there. Its quite possible part of your linkage is broke. The pins that hold everything together get pretty corroded and the clips holding the pins in can break off.

 

Fish you are not correct either my friend.

There is one shifter that serves two distinctly separate functions and each has it's own linkage so to speak.

Movement of the shifter toward the driver's seat SHOULD LOCK the Center Differential by CCW rotation of the DIFFERENTIAL LOCK SELECTOR ASSMBLY - ITEM 35- IN THE ATTACHED EXPLODED VIEW. It is totally independent of whether the transfer case is in LOW or HIGH. The shifter moves several inches. Movement back to the right should unlock the center differential. This can be accomp[lished at any speed as long as the wheels have not lost traction and thus would be spinning freely.

Land Rover Discovery I Transmission Levers, Linkage Parts Available from RoversNorth.com

Shifting from HIGH to LOW and back can only be accomplished with your transmission in N and below 5mph. Anything else will cause damamge if it shifts at all.

Illumination of the dashboard indicator is accomplished by item 39, the CDL Switch applying the ground and lighting the bulb. Often this plunger mechanisn gets bound up from debris/corrosion and may require replacement. Mine Did.

The side to side motion of the top of the lever is transmitted via the shown linkages to the little connector link -item 31- to achieve rotation of item 35. This can be manually accomplished by placing a wrench on item 30 NUT and rotating it in a CCW direction looking down from above. Multiple pictures are located in the pics link in my signature as are some interesting videos.

I completely removed my linkage and rebuilt it bu replacing all the clevis pins and clips because they were severely corroded. This entire mechanism is exposed to road elements from below but requires removal of the console and the rubber boot for access.

Look at my previous threads for more details if needed. And check out the links in my signature. Been there done that.

 

Hmmm, gotta disagree. I know quite well how the CDL shifter works and that it controls two separate functions. Maybe I didn't link to drawings and RAVE pages but nothing I said was incorrect. There are essentially 9 positions. Not all may do something but you can feel the shifter moving into that position. These positions aren't defined by a plate restricting the levers movement, but by the action the lever performs. Those actions are:
Lo locked. Lo neutral. Lo unlocked
Neutral locked Neutral neutral. Neutral unlocked
Hi locked. Hi neutral. Hi unlocked
Each position above corresponds to where the CDL shifter will be when in the positions. The CDL shifter position is a result of the movement required to perform each action, not a result of a patterned plate that the CDL is restricted to moving through.
This may be a simplistic way of looking at it but it is correct and easy remember.

 

It may be easy for you to remember but you created additional positions. The CDL being locked is totally independent of the transfer case ratio selection. N on the short shifter does not have a N Lock and a N Unlock and an N. But suit thyself. Not worth arguing about. You merely turned 5 settings into 9 positions. I do not think that will help him much at this point.

If the linkages are bound up, it is never going to move the required pieces to lock or unlock the center diff. It locks by means of an internal yoke physically locking the ceter diff.

The real point i would like to make is that he needs to understand the mechanism that is there. That is why I refered him to the exploded view from the Rover's North webpage. It shows it all quite well and identifies the individual parts.

If his is acting up like it is, especially when you go "jamming" it into gear, light not coming on , then it not unlocking, he will most likely need to tear into it. He shoiuldn't need a new or complete transfercase or even a replacement linkage. He may need one or more of the parts I showed in the attachment.

He may get by with a good repeated spraying of PB Blaster. He may be able to rotate the nut I referenced with a wrench. The first time I got mine to engage was after rebuilding the linkage, a thorough cleaning, greasing the top box with Lucas Red and placing a socket on an extension and a speed handle and rotsaing that nut CCW.

There is also many occasions where one may want to lock the center diff with the transfer case in H. My point is simply that he should understand how it is supposed to work, how to correctly shift it, and that it should move freely and turn the light on and off with no problems.

If you did not like what i said or how I said it, please click the appropriate link below. Enjoy.

 

Danny, I actually agree with most of what you said. The part I didn't care for was when you flat out said I was incorrect when, in fact, I was not. I also never said you were incorrect. There isn't always a "you're wrong, I'm right" situation. Sometimes two people can both be right.
Anyways, there are actually 9 positions. As stated some of them may serve no function but the CDL shifter can be moved into them. I called some of them Neutral. When a TC is neither in Hi or Lo I don't know what else to call that position other than Neutral. Same goes for the CDL. To pretend like they don't exist and that the CDL shifter cannot be placed in those positions is not accurate or helpful. I was in my truck last night on tje pgone with Bill and placed the CDL shifter into the Neutral Neutral position, along with all the others. There is not much point to doing so(although it is helpful to install driveshafts by being able to spin the TC end) but it is possible.
I never said there wasn't a point to being in Hi Locked, I do it fairly frequently when wheeling. I said there isn't much point to being in Lo Unlocked. I'm sure its been done, but probably not too often.
I'm also quite familiar with the RAVE and exactly what does what on the TC, but thanks for the links.
I think we both agree that the center console needs to be pulled and the linkage investigated.
Cheers.

 

Brett and Danny,

BOTH of you have been extremely helpful. Thank you!

Judging by BOTH of your explanations, it appears that my linkage is jazzed up. Now all we need to do is figure out how to un-jazz it.

For the short term, I would like to learn what I can do to get it back into Unlocked-High gear so I can get it back to being a daily driver. I know that some D2 guys who dont have a linkage can crawl underneath and switch things around. I just want it to get back to where it was so I can drive it.

For the long term, I would probably have to remove the linkage, clean it all up, and replace the broken bits. This is fine, but I would rather save this project for another (warmer) day.

What do I need to do to unlock it? I took the boot off this morning hoping to hack away at it with a screw driver or breaker bar but there was a bunch of dampening material in there and I did not have the time to deal with it.