Every since Ive had my truck (bought it with 60,000 miles) While in first gear it makes a whining, raoring sound then when goes to 2-3-4 it stops. Only does while in 1st gear what is this?

completely normal, has to do with the heavy duty gears in it. GM will tell you the same thing too.. No repair attempts should be made and you could actually make it worse.

thanks