My Dodge Ram started making a whining from the rear the other day, so I picked up some wheel bearings and axle bearings/races from the parts store. Backed it up to the shop , jacked up ,pulled the differential cover off and gears looked fine thank goodness. Got the bolt for the pin spun around...
Have a 08 5.7 with 140+K on it. Not any big problems at all so far. Had to replace the sway bar links and u joints , that would be the biggest things so far.
Mine was doing the same thing and eventually only worked on high speed, turned out to be the motor.
Those things got me and my buddies kicked out of riding ATV's up at Warwoman in Rabun county. Most fun I ever had riding trails, did it for years until horseback riding really picked. ATV's and horses don't mix.