05 e500 4matic transfer case
 

Ok a buddy replaced his passenger front axel but it never engaged into the c clip. He drove about a block then started to freewheel no transmission engagement. We removed the axel and can now see a roll pin, ( elliptical gear pin I think) in the spline shaft which is in front of the c clip. Tried pushing it up with a long screw driver but it seems stuck. Can anyone shed some light on this for me please.

Well all solved actually there never was a problem we had a senior moment never knew that roll pin was supposed to be there. Anyways we intended to replace that diff and had everything ready to unbolt the subframe when we had another look and then realized our miss adventure. What a bone head move that was....