Yes you need to engage or cycle through all the modes reagularly so it dont stick. My buddy has a Gen 3-2001 model and he has had problems with the Diaphram stickin on the front diff and not wanting to engage. Just gives you and excuse to get out and go 4wheelin <img src="/forums/images/graemlins/wink.gif" alt="" />

Bret, I would think you need to go through and check you vacuum lines to the front for leaks as well as the diaphram to see that its workin... <img src="/forums/images/graemlins/smile.gif" alt="" />

03 Montero XLS, OME 2"suspension lift,Full skid plates, Extended Diff/transfer breathers. 34 LTB's, Winch w/syn rope, Locked front/rear.