Looking for clarification- I think I've been working under a misconception. I thought the pattern for the CDL shifter was like an "H", with the middle of the H being a sort of gate between locked or unlocked. From what I've read here, in the sticky section, and on Youtube, it looks to me that the pattern would be more of a box or square, and that I can shift straight over to the left from either High or Low to lock the center diff, is that correct? Mine's a little stiff, so it's hard to tell. Interestingly enough, my 99 is a D1, but I ended up with an owner's manual that shows all the controls and such for a D2, so no help there either.

 

The CDL shifter serves two distinct and separate fuctions. If it is working properly (most used ones are not unless they have been used on a regular basis), you should be able to move it to the left (toward driver's seat in US models) in either high or low at any forward speed as long as the wheels have not lost traction. It moves a few inches as far as the travel.

It is intended to allow you to shift on the fly when you need the additional traction. You do not have to stop, but do not wait until you are stuck to engage it. Do not try to engage with the wheels spinning from loss of traction.

When you no longer need the additional traction, move it back toward the passenger's seat to disengage. Do not drive it on dry pavement with the CDL engaged.

The same shifter also is used to select HIGH or LOW settings for the transfer case.
To do that, the transmission MUST be in "N", speed less than 5 MPH, unless someone has removed the interlock solenoid. Some people have removed the solenoid thinkinhg they are "fixing" something. With the solenoid out, it will allow shifts regardless of whether it is in gear and can lead to significant damage if shifted while underway.

There is no H pattern. If the shifter is in any other position (somewhere in the middle) you will not have the proper traction (it may pull somewhat, grind, or be in an undetermined state). If it is slightly out of position, the shifter will shake or vibrate while driving. If this happens, slow down, and move it to where it should be.

The shift likages are exposed from underneath the vehicle and are prone to corrode from thye exposure to the elements. Especially if you live in an area where road salt is used in the winter time. Also mud, road grime, and anything else tends to enter the area and give you problems shifting.

There are multiple writeups on this site and several others detailing all of this and how to resolve it. Did you try a search on CDL Shifter?

 

Thanks for the clarification, bro. I went out today and fooled around a bit more with it. I get what the CDL is for and how it works, I was just wrong about how it shifted in and out. Thanks again.

 

Use it often to keep it from freezing up. If it is stiff, it may need to be lubed good.