2006 RX8. When I turn in somewhere slowly the rearend roars and grinds. What's wrong? Is it covered in my extended power train warranty?

 

depends on whats wrong.
what extended warranty do you have? Most extended warranties are sold through a 3rd party and they usually have all kinds of restrictions / limitations.

My advice is to go over your paperwork, find out what type of deductible you have, what the warranty covers, and then get the vehicle inspected.
Sounds like it could be an issue with the differential? Who knows...

 

your tires are unbalanced or your rotors are pooched?

 

Rear brakes?

 

my rear end roars sometimes too

 

if it does it only when turning... could be your wheel bearings


jack up the rear and check the wheels for play ( up and down, left and right) if you here or feel is clunk then its the bearings

if that checks out, then put the car in neutral and manually spin the rear wheels, have some listen at the diff to hear for noises

 

did you put cheap tires on? they tend to make more noise.