or you could just use this link for a part number (viscous coupler AKA 'Center Differential Assembly') to get exactly where and when it's used. Cool!Might I ask: What happened?
http://opposedforces.com/parts/ can be a useful site for researching compatibility. For example, I just did a quick look at Impreza and then Legacy (Outback) MT extension cases, and they're the same part number (32130AA171). Same could be done for the other parts needed. (Impreza and Forester would also be the same.) This could give you both model-to-model (Outback/Legacy/Forester/Impreza) and year-to-year (and even build-date) compatibility comparisons. Here's an example page: http://opposedforces.com/parts/lega...ion/mt_transfer_and_extension/illustration_2/
http://opposedforces.com/parts/info/38913AA101/ (next version, replacement, I believe)
http://opposedforces.com/parts/info/38913AA102/ (latest, but not in webpage so 404, yet?)