I suspect the grinding when you try and put it back in park is because the drivetrain is freewheeling, as there is no load on it. If the cad isn't engaging, then everything just spins freely.... Probably even putting it in neutral for a few minutes would only reduce the noise, not eliminate it.

is your 4x4 lite coming on? It'll probably make some funny noises while the cad is trying to engage.

 

My 4x4 light does not come on at all. It does make some interesting noises when trying to engage, but just won't budge in 4hi at all.

 

Cad isn't engaging. Likely just a vacuum problem. Check the lines from the t-case, to the front axle. The metal lines that run along the frame like to rust out, and the front axle stops working.

 

Went back and toyed with it and it shifted right into 4hi no problem and I finally got to drive her home. Now I'm waiting on my yolk to be replaced, and after that's all done(may have to get it all balanced) and I get new u joints, I think I'll finally be back on the road!

 

We havin' fun yet?

Good Luck!