The maintenance schedule calls for inspecting this. Is there really such a thing as a Front Differential in the Prius? If so, has any one checked to see if the oil is really Lifetime (not taking Toyota's word for it, but via a UOA)? Thanks.
Differential is part of the transaxle. There are some good threads discussing transaxle maintenance in the GenIII Maintenance Forum below. This one for example: ATF fluid changes ARE Required. | PriusChat
The "inspection" process in the Toyota repair manual consists of checking the oil level, nothing else. The thread Tumbleweeed posted a link to should answer your questions about it being a lifetime lube.
So, if I change the ATF in the transaxle, it will also automatically take effect for the Differential (since it's part of the transaxle), correct? IOW, no separate plugs to open and check/fill than the 2 (drain and fill) plugs noted for the transaxle in the thread you referred to, correct?
Yes, a transmission becomes a transaxle when it includes the differential. Transaxle - Wikipedia, the free encyclopedia
Yes but, not all transaxles use the same lube for the transmission and differential. Prius does though.
I'm puzzled. The US Maintenance guide says to inspect "automatic transmission fluid" and "front differential oil". Two separate items. Then when I search the Repair manual for "differential" I get several disparate hits, none seem remotely connected to oil, etcetera. Mostly electrical. Then the Canadian Maintenance Guide, which valiantly encompasses maintenance on every vehicle Toyota sells in Canada, says to service every 12 mo or 16000 kilometers: and further on:
Since you mention the Canadian guide covers all vehicles (including non-hybrid), the applicable term for us here seems to be "hybrid transaxle". Since it's not listed in the items needing replacement of fluids in the last quote you provided, it seems like it's indeed consistent with the US Maintenance guide; i.e., the Canadian guide is NOT asking for replacement of fluid in the "hybrid transaxle".
You're right, here's Toyota Canada maintenance, for all their vehicles. Two whole pages, LOL. One caveat, while the front page of this pdf says "owners manual supplement 2010", it varies in wording from the same titled physical book we got with our car. In particular, there is some variation in the transaxle fluid section. That said, I don't believe either version says to ever change the fluid on a (3rd gen) Prius. In our paper version the wording regarding applicable models (for transaxle fluid replacement) is very convoluted. To the point of being unintelligible.
