all there is, is splines, kind of twist back and forth a little while pushing it in, prolly time for a new seal now also.
Yep.  With the driver' side wheel on the ground, you should be able to push it in by jiggling the front driveshaft until the splines align - assuming the dif is not locked.  As 94track suggests, while you can get to it, replace the seal on the output of the axle housing. ÂÂ
Seeing your post while I was typing this one, it looks like you need to take it all apart anyway and see what's keeping the shaft from properly seating. You may need to inspect the splines on the dif output to see if they are banged up. My guess is that you have some debris in there or a damaged seal is keeping it from seating.
I am a bit on the anal side, so I'd take it all apart and check/replace the hub seal and the boot covers if they are damaged.  The parts are cheap but the disassembly is a PITA until you do it a couple of times....
