While I was in the mud in my 91 trooper 2.8l the front wheels would only engage some of the time. The front CVs clunk but the guy at the parts store said that they will clunk until they break. The plan is to replace them but is this the problem?
A friend says that I have a chain driven transfer case? and that the chain might be loose?
Another friend says it may have something to do with the vacum to the transfer case, but he owns a jeep.

So when I stick it in 4 I go forward to engage and hear all the necissary clicking. Then when I get in some mud and start spinnig only my back tires seem to spin. And my front do nothing. Any Ideas?

Any help is apriciated