Did you try to engage manually on top of case? Might get more turn that way.

 

Keeping the CDL engaged by pushing on the fork is not doing the t-case any favors. The fork will be getting worn out as will the dog clutch. You need to see if the linkage you are using is out of adjustment and keeping the CDL from fully engaging.

 

I have a mechanical linkage...

My main concern is finding out what's wrong with the rover so when I drive there is no play in the front driveshaft

 

It looks like the reason I'm having trouble keeping it in diff lock is when I use the accelerator the drivetrain shifts with the worn out mounts, and it appears I didnt cut the plate enough and it knocks it out of gear.

Go figure.

As for the driveshaft... I can't tell if it's bad or not. How much play should there be in it if any ?