If anyone has experienced this before please let me know. My 99' Legacy 2.5 auto thuds/shudders on kickdown. It only happens at high cruising speeds and when i'm coasting to a stop then accelerate e.g at roundabouts.

Have checked engine, transmission and diff mounts and they all look fine.

Any ideas??

While i think on? does anyone know how to read and clear fault codes off a 99' legacy. Earlier models you could connect the contacts under the dash and watch the check engine light??