my front diff sounds like it is grinding...it does it in 2hi 4 hi and 4 lo... could this be to low fluid? i just had ford put the 4 inch rancho kit on and i dont know what the tech did with it...or could this be maybe the torque converter whatever it is it sounds like its up front...thanks guys by the way its a 2004 fx4

 

Take it back & make them diagnose it. If it's related to the previous work, they have to fix it free. If they say it's not, they'll give you an estimate to fix whatever it is, but at least you'll know what's going on.