Hi I own a 2012 Subaru Forester with a 5 speed manual transmission. When I shift into 2nd or 3rd gear and let off the clutch, there is a split second rattle sound when the rpms are low (<1500) but disappears as soon as the RPMs increase. This sound doesn't occur in 1st, 4th or 5th gears. it also doesn't happen if I rev the engine a little before letting off the clutch. It shifts and drives perfectly aside from that noise and both the clutch and transmission fluids are full. I read on some Corvette forums about a similar sound coming from a dual mass flywheel being normal. Is that what's happening?
It sounds like your throwout bearing is about to take a dump.
If it is the throwout bearing, shouldn't the sound occur when the clutch is pressed down?
Not always. Whatever it is, you're going to have to pull the trans to see what's wrong.