I have a 2004 2-dr 4x4 chevy blazer s-10. This is the second one I have owned. Both of them have the same issue. When driving down the road at 50 mph or more it starts to whin, kinda roar. It sounds like a jet engine(turbine) when you slow down it gets real loud and then stops when you stop. It makes a clunk right when it stops making noise. Under 50 mph it does not do it. Can any one give me something to go on????? The blazer only has 40,000 miles on it !!!
Thanks
Kathy

 

Are you driving in D or OD?

 

In drive. It's an automatic.

 

Does it go away when you engage 4wd? Even if it doesn't, the problem is likely with the front axle engagement. Have a read through the thread linked to below:
4wd Front Axle Clicking When in 2HI - Goes Away when in 4HI/4LO

 

Could it be the fan clutch?

 

Yes it does go away when I put in 4wd. But it is not a clicking sound that it is making it is a loud whin/roar. Any thoughts on what it might be ???