ATF fluid changes ARE Required.

There is no such thing as a lifetime fluid, what ever your definition of lifetime is. All fluids breakdown, oil, gearbox, transmission, anti freeze, brake, power steering, ect... The recommendations given here to change the ATF on GEN III's range from 5,000 to 30,000 are feasible based on the documented facts the "geeks" have gone the extra mile to provide. The samples I took at 30K, 40K and 45K were enlightening and ATF is now part of my 5K oil/filter change regiment. I use the suggested Toyota 0-20 and WS because with my duty cycle there would be no benefit to using anything else "at this time". Thanks for the heads up on Inverter fluid Bob.

 

Check out the color of my fluid at 34,600 miles. It's a thick opaque burgundy color.

 

That is terrible looking! Did you run through a swamp by any chance?

 

That's almost as bad as it looked when I changed the fluid in the '11 at 13,000 miles.

 

Really?

 

It didn't look as good as I expected it to. I guess I expected it to look like clean trans fluid. This stuff was not clear and was more purple-red with a hint of chocolate. LOL

A huge thanks to The Critic for coming over with all of the tools and fluids to change my oil and transaxle fluid. Then change the oil in girlfriend's daughter's Civic and inspect the suspension. I swear this guy lives to change fluids! he should have been a dialysis nurse. Ha!

 

I was playing around with Torque today and monitoring temperatures. I noticed that with 100% lower grille block, inverter temp and MG1 temp went up quite a bit during low speed hypermiling with lots of EV use compared to steady state freeway driving. I wonder if hypermiling/city driving is much harder on these parts than lots of freeway miles.

Here is are two screenshots I took.

While driving on the freeway. Ambient temp was 46F.


After driving for a couple blocks with lots of EV use then sitting parked for 10-15min or so. Heat soaked kicked in like crazy while parked compared to driving.

 

Cool, I also have Torque, but didn't use it yet in Prius. What is MG Cool? Can you also monitor MG2? 185F for MG1 sounds high. According to a paper on electric windings I referenced on another thread, every 10C increase in winding temp cuts winding life in half.

 

Did you keep a sample for analysis?

Was there any unusual odor?

Bob Wilson

 

Unfortunately, we did not. The odor seemed normal for used WS-ATF. When I had the ATF replaced on my 2011 at 15k and at 32k, it was a clear, bright red both times.

 

This is a photo of my first transaxle oil change . . . in 2005.

It had a distinct, paraffin smell. Over the years, this remains my most memorable sample. I've had others sent but only this one even came close. I have no idea what caused it to be so opaque but the particle count was 'off the scale':
2003 Prius - Cold Weather and Transaxle

The transaxle sealant is red tinted from a ferrous material and silicon based. But after the initial leaching, it diminishes over subsequent changes.

Just a though, always have a sample bottle . . . I use half-pint or pint sized water bottles and keep one or two empties in the car. The last bit of water soon evaporates and 'voila' . . . sample bottle. You can always toss it with the oil at the recyclers but it is so hard to grab a sample without one.

One 'minor' concern is we're always on the look out for any coolant invasion of the transaxle. Water in oil is very bad news. When I saw the drain photo . . . well I'd like to suggest . . . treat it as the first of a two-part flush. Within the next 10k miles, do a second change and this time have sample bottle? It doesn't have to be analyzed but . . .

My studies of the NHW11 transaxle which has a removable (and cleanable) pan, suggests there is about a 15% carry-forward. I have no studies of the NHW20 or our ZVW30 but Jeffery Denenberg has a continuous series of NHW20 samples and I suspect partial fractions could estimate the range of carry-forward.

Bob Wilson

 

Will do, Bob. I know Mike likes to change ATF.

Question, I bought some WS for my GenII back in 2008 or so and forgot about it. I recently found it (unopened). Do you think it has been sitting to long to use?

 

It's a "lifetime" fluid . Actually it should be fine, especially if it was unopened.

JeffD

 

MG cool is inverter coolant temp.

I can monitor MG2 as well but when I would look at adding more gauges it always appeared to be about 10F cooler than MG1 so I didn't add it. I will add it now that I have more time to make changes.

I will also run without grille blocking to see if this changes MG temps.

 

Very hot inverter and MG2. Maybe Gen III runs much hotter than my II. I would think it would run even cooler with its outboard radiator.

Maybe someone with an IR Thermometer could check temps of a III Inverter now and then. I have on my II and the Inverter never ran above 125 F even in 80F stop and go Florida days. But heat sink after park was crazy it went to 160 somedays 5 mins after park. My Inverter ran its coolest after I Coolant change at 25K miles. Very happy. Dropped almost 4 degree's in temp.


And I thought what Bob thought too. That trans fluid went milkshake on you which in engine oil immed. reflects coolant contamination. But I doubt that is the case as your trans would not last long leaking coolant into the fluid and the I coolant reservoir would be low and dirty too. I would change it again real soon like after 5K miles. It looks like diff oil gets with hypoid gears.
Diff oil turns into milkshake.

Still...strangest looking WS or ATF I have ever seen.

But at least you didn't maim yourself F8L.

 

It was a dark magenta color as compared to the new fluid.

 

Honestly I expected the fluid to look new so I didn't bother with a sample for analysis. By the time it started draining I had just enough time to snap a shot and still did t think about plugging the drain until I could get a clean specimen container. Hindsight is 20/20. I'll be ready for the next change though.

 

Bill please report your results with Passport as I am a Prog customer and was thinking of trying that 2.

 

Btw, I used "Wearcheck" for my last UOA. These guys:

Wear Check International - The Oil Speaks…We Listen…You Save

I liked them they showed TAN as some don't and its only $25.