WRX 2011, 40k miles. Almost since birth has this problem: if I get to 60-70mph, switch to neutral, let RPMs go to idle, then try to engage 5th - it grinds. Dealer replaced oil first, then replaced synchronizer. Helped for ~200mi, then same thing again. Now they say that local service rep claims it is by design, and I should engage 4th - will be fine. It is fine, I can get 4th or 3rd; it grinds only on 5th. But it doesn't make sense to me.
Does anybody else have this issue? And yes, I know you should stay in gear; I just have this 3 mi long hill going home