When I engage switch for 4x4 front wheels lock in with the wheels off the ground . They seem to drive until you put heavy load on them .I can't get them to spin in the mud .I've been told it's just a clutch pack that engages the front end .It's a Spicer trans and the unit is mounted on the bottom of the housing witch looks like it will unbolt from the trans .Are parts still available for this and am I headed in the right direction ?
A Serial Number would be a great help in answering your question regarding parts availability. If you don't have a Parts manual you might struggle identifying what you need.
7BC03463
A quick look shows parts like the clutch discs for the Spicer transmission are still available. As I said before you really need access to a Parts Manual appropriate to your Serial Number. the Cat Publication reference is SEBP1885. Registering on avspare.com/ might be a good bet.
Does the drive shaft to the front axle keep turning or not?
From avspare
No the driveshaft stops turning