I have a 05' 4.7L 4x4 with the fulltime AWD. All of sudden while driving it was like the trans slipped out of gear and I get a loud whining noise, pulled over and when trying to put into park or reverse it grinds. The odd thing is that I can drive no problem when I have it in 4lock.

A dodge mechanic told me that if its whining that means the trans pump is starved for fluid, and the trans pump filter is sometimes the cause of the whining sound. So over the weekend I dropped the pan and changed the filter...didn't work.

Any suggestions or help out there? How can I drive in 4lock but not in normal mode?

 

Driving in lock, but not normal, tends to point to the problem being in your transfer case, not your transmission. Perhaps your transfer case is low on fluid, Could also be a plugged transfer case pump. Either way, I don't think your transmission is the issue.