is this a symptom of the cam shaft synchronizer going bad

Hum in the transfer case when driving in 4x4 high just started. The hum seems to be getting louder. Only makes humming noise when you accelerate.

I was having problems with the gear shifter not working, I took it to the dealership and they said it was the brake light fuse.

It still runs hot do I need a fan cover

I have the 3.0 motor, after motor is warmed up i get a rattle noise at 2500 rpm,s . this happens when i shift gears, after the rpms increase the rattle goes away. when i downshift when rpms are high their is no noise. other than that engine runs fine. 129000 on engine.