trophyhunter

Hey guys, new to the forum and could use some advise please.
I just got a 2000 Grand Cherokee limited 4L 6 cylinder, it has the Quadra Drive (249 series?) and the front wheels were not turning at all, there was absolutely no noise at all out of anything, shifts well but only had rear wheel drive so I went to the jeep dealer and got the right t-case fluid.
Serviced the transfer case as I found it to be very low on fluid, the front wheels are locking right up now on snow and ice but I am getting a loud chattering/grinding sound now the t-case is full of fluid.
I suspect a fluid coupler has gone bad?-this is my first Jeep and any input is greatly appreciated, THANKS in advance for the help.