I have a S-10 blazer and a few weeks ago it started making a sound kinda like the wheel on the price is right. It speeds up when I get on the gas and slows down when I get on the brakes. It has also started be very sluggish when takin off from a redlight or something. I had the drive shaft and u joints looked at and was told they were fine. My question is does this sound like the differential is messing up or is it just the gears. This is my only mode of transportation and I need to get it fixed as soon as possible.