So my TJ makes a whine/ whistle between 1800 and 2400 rpm while driving... It sounds similar to a supercharger only quieter. Its possible the sound continues after 2400 rpm and I just can’t hear it over the engine roar, and only it occurs during engine load/ driving, not when parked/ in neutral. It’s noticeable while in first, second, and third gear; after third gear I believe the wind noise drowns it out. Someone told me it could be the exhaust manifold gasket?