Just got this '04 Discovery and finished head gasket repairs. Engine runs fine now.

Is there a trick to putting this into 4 wheel drive. I put trans into neutral and tried to move from high to low, but shifter doesn't budge.

Am I doing something wrong?

 

if your truck is moving it is in four wheel drive, your only option is high or low transfer.

 

If you are saying you are unable to shift from high to low or high lock to low lock, there is a good chance your shift solenoid, in the console, has failed.

 

The truck should be rolling at a walking pace and in neutral to shift from high to low range or L-H the diff lock can be engaged at moderate speed but not while on clean dry pavement.

 

I have never had to be rolling to shift from high to low, this is an electrical issue he is having.

 

I have to be rolling to shift mine from lock to unlocked, hi to lo no.
You can do it without rolling but I think it makes the gears mesh easier.
I have found it best to shift the transmission to neutral while rolling forward or backward at a slow walking pace.
Since you have a '04 the shift linkage is a cable and not a actual solid rod type of linkage.
The shift cable is inside a casing and it may be rusted and stuck.

 

If it is very difficult to change I would suggest NOT trying to get into low until you figure out if it's rusted. If you break the linkage and it stays in neutral or low you're in way worse shape.

 

If it turns out that it is not a solenoid issue you could buy yourself a can of seafoam DEEP CREEP penetrating oil and spray the top and bottom of the cable. Do this for several days, trying to get the shifter to move just a little bit more each day, do not force it.