I have an 04 discovery, I know it is supposed to have a locking Diff, but the guy I got it from said the tranny was replaced at a 100,000 miles I noticed that the 4x4 shifter does not have the locking imprint on the top of it. I tried moving it over but it wont lock into anything...to be fair I cant get the shifter to lock into low..I think the linkage needs to be lubricated.
My question is how can I tell if the transfer case on there does have locking ability. I know some of the older cases had it and you had to ad a linkage.

Are there any pics of what a transfer case with the locking diff would look like, so I can crawl under and see if it does have it. Once I know that then maybe Ican get it hooked up.
Thanks in advance

 

The locking t-cases have a 2-flat actuator bolt sticking out of the top, near the front end:



CDL lock circled in blue

You should be able to locate that from underneath the truck. Unless something truly disastrous happened it would have been strange that the t-case and the transmission were both replaced, so perhaps the PO meant that the transfer case was replaced.