Hi, fellas!
Just bought ecoboost "15 Mustang with manual gearbox
The issue is when accelerating fast at around 4500 rpm hearing metallic sound from the gearbox and rpms are struggling to go higher that 4500. When pressing the clutch and switching gear this immediately disappears. This happens only at 2nd, 3rd and 4th gear. When doing this in 1st everything is perfect, reving up to 7k rpm

The oil in gearbox was changed 5k miles ago( Mileage now is 23k miles) Used Kroon-oil SP GEAR 1081...

MUSTANG "15 2.3 ECOBOOST MANUAL METALLIC SOUND AT 4500 RPM