4wd not working????

[2_Late_I_Won]

I have an Agco Challenger MT275 40.1hp Diesel tractor with sync shuttle shift. The way mine engages is there is a lever on the left side floorboard that you press down to engage 4wd. I was using it today using the FEL and had no issues. I went in to go rest and eat a few bites and now it doesn't engage. There were no grinding noises, no rough engaging or dis-engaging. It just seems like the lever has no tension in it. In order to fix this Im going to have to split the engine and tranny right?
Or could the be any other way to fix this?

Thanks in advance for your help.

[BobP]

Check the linkage . Is there a roll pin that connects the lever to where the stub come out of transmission . I have seen them break off ,back off or strip on some other tractor types . Look for the easy fix first. When you push down on lever does it actual move the shaft going into the transmission .