4 wheel drive noise

[rifleman69]

I have an annoying and somewhat loud noise coming from my 2001 sport trac. It is somewhat like a gear or grinding noise, peculiar thing is that it only comes on while in 4 wheel drive. Once 4x4 disengages noise goes away.

I am thinking front differential bearing or somthing in the transfer case but could use some help to diagnose it.

thanks in advance for your help.

 

[John_Rock]

Our 4x4's are live axles, meaning everything in the front spins all the way back to the transfer case whether you have the 4x4 on or off.

 

[swetrid]

Make sure your tires are all the right size and that the circumference is less then 1/4 inch difference or you will cause tranfer case issues. Just say you have 2 Goodyears on the front and 2 BFG on the rear could cause a issue and noise like you are experiencing.