Hey I've got a quick question, I have a whistling sound in the rear of my truck (2004 F-150 Supercrew Lariat) when I accelerate between 40-50 mph. People have said it is the rear differential. How much can I expect to pay to get this fixed? And is there a need to get it done right away, or is it something that won't harm the truck if its not fixed immediately? Thanks for the help and any info you can provide me.

 

id atleast have it checked out.. open it up pull the diff out and check your bearings and races.. it could be as simple as a bad bearing or two.. in that case you can buy just the bearings and the races and replace them...