anddddddddddddd..I wonder how I know this ?!..lol.Shade's right. 05-08 have a weak first gear. The replacement part offered by Honda is upgraded and stronger, so when you replace it you won't have the problem again, but replacing it requires tearing the engine all the way down.
New gearset is only about $60, and you'd need a gasket set to reassemble, so parts aren't expensive, but the labor is pricey if you don't do it yourself.