Sometimes when I disengage my four wheel drive it takes some time to disengage and when it does there is a lound clunking noise from the front end. Any ideas where to start?

My guess is your t-case or front drive shaft. I would check the fluid in the t-case and check your drive shaft for worn joints. Also check to see if your tranny mount is ok. If the rubber is torn, it could cause excess movement. Good Luck!!