Check engine and exhaust mounts for condition and security.
Check the propshaft and exhaust for any 'shiny' bits that would
indicate rubbing.
I had exactly the same problem on a RWD Merc. One of the front
engine mount bolts had come loose and one of the exhaust mounting
rubbers had perished.
When powering up a hill and going round a bend, the engine mount
allowed the extra torque from the engine to twist the drivetrain
out of line and meet the exhaust system which also moved because
of the perished rubber mounting, and the two rubbed together.
Not saying this is your problem, but the combination of putting extra
twist on the engine due to increasing the torque by powering up a hill,
and putting centrifugal forces at work by taking an adverse camber
bend at the same time, would indicate that a rotating mass is being
brought into contact with a part that it normally isn't when these
forces aren't at work.
Do you have any other unrelated symptoms such as vibration, steering
wander, or brake related problems that would indicate a problem in
suspension or steering bushes?