I think every 60k miles is a good interval. It's a bit conservative, but Toyota recommends every 60k if the vehicle is operated under very severe service (i.e. towing).

 

I'm curious whether the fluid referred to in that document is the inverter coolant? "Hybrid System fluid" is a very vague term...

 

Please see my previous post. The maintenance printout I was given by the dealer says 100,000km (60,000 miles).

 

The booklet that came with my car, "Scheduled Maintenance Guide, 2007 Camry Hybrid" does not mention any transmission oil change at any interval and it goes up to 120k miles, but it does list change of spark plugs at 120k. However it does mention inspection of transmission fluid, engine/inverter coolant among other things, so I wonder how one supposed to do that , especially tranny oil. I would suggest that if anybody decides to change the oil, he/she should drain some of it into small bottle and send it for analysis together with fresh oil for comparison. That should give us some idea if and when oil should be changed in the future. I'm planning to change mine at around 50k, which should be sometime around next summer. We should be looking for viscosity drop (no more than 15 %) and foreign particles like silicon and metal. Also it would be important to replace it with Toyota WS oil, other brands may not be compatible with electric motor's coil insulation and do more damage than good in the long run. I think break fluid and coolant also should be changed at around 100k to avoid any problems.

 

It can last a long, perhaps life of your car, since there is no friction parts like clutch plates, so no contamination.

 

I asked the hybrid tech how often the lifetime transmission oil should be changed when my TCH was in for it's 25K service. He said Toyota recommends the TCH be changed every 90,000 miles. Sounds like a reasonable interval considering there are no clutches, valve bodies, etc to wear.

 

It's funny how every time someone asks, they seem to get a different answer on these types of things...

 

Maybe, because the car and hybrid technology in it is so new , there are no long term, large scale studies? The oldest Prius on US road should be about 8 years now and that model used different oil anyway. Also cars are driven in different places, from frozen Canada to heat scorched Arizona.
And if there is no friction inside, why would they be using oil to begin with?
There are bearings inside, there is gear friction and heat from electric motors. The oil should last longer than in regular transmission, but who knows how much longer. There were transmission failures in original Prius and testing showed lower viscosity in used WS oil as well, also particulates like silicon kept increasing as oil was getting older. If anybody was hoping to drive the car past 100k maximum warranty Toyota will issue, oil change is no brainer. On the other hand I highly doubt the tranny would fail in the first 100k with or without any oil change. it's past 120k I would start worrying about, because once the oil loses it's viscosity and preserving properties the damage can be done rather quickly.

 

Even the conventional Camry's have no transmission dipstick these days. They are sealed and the fluid is not on the list of things for servicing. The only mention is if the transmission itself is serviced to not reuse the existing fluid but nothing about changing it periodically. Kinda makes you wonder doesn't it?

 

That's why I'm confused...
You figure it would be in the best interest of Toyota for them to disclose a mileage of when to change the fluid.

If you have TCH owners thinking they never have to change the fluid, and have burnt transmissions on their hands, they're not going to be happy campers, myself included.

I think Toyota should release an official statement on life expectancy, and service instructions on the fluid....