The transaxle has less than 4 quarts of Toyota type "WS" transmission fluid. It is suppose to be the life of the car fluid with no scheduled change interval. In the Gen 2 Prius, after some used fluid analysis, it was generally seen that changes at 60,000 miles was prudent. Wayne
Following the major transaxle redesign for 2010, it would be great to get an early look at the fluid condition. I bet somebody in Huntsville AL will do that
Welcome to PriusChat ... Do you like Vietnamese? Chinese? Beer? Perhaps you'd like to get together someday for lunch with the Huntsville bunch? Bob Wilson
C'mon you guys - you can't get real Chinese food in Huntsville. However the city has several other strong points.
Is there a filter in the tranmission pan? Since there is less than 5 qts, I would change the ATF fluid every 20k. It's cheap insurance to keep everyting running well.
There is none discussed or shown in the SAE paper. It seems a little aggressive. Based upon transaxle oil testing, the earlier NHW11 and NHW20 appear to respond best to: 30k miles - NHW11 60k miles - NHW20 It will take a little time to use transaxle oil testing to figure out the best schedule for the ZVW30. However, I plan to start testing my wife's ZVH30 along the following schedule: 5k - samples of engine oil and transaxle oil to send off for testing. I'm expecting the first sample to show elevated Si levels and any early 'lapping' debris. +2k, +5k, +10k, +20k, +50k - a semi-log scale to monitor viscosity and elements schedule. Right now, I've been waiting for the paper manual but if it isn't available by August, I may go with the electronic version. Bob Wilson
Bob, I'm very interested in following your research. Any chance that you can begin a project thread? I'm on other car forums, and project threads are pretty neat and interesting and you seem like the perfect candidate!
I know from most Toyota designs, there is no dipstick. Once you drain it, you open a plug on the side of the transmission, and fill with a pump. The procedure (dumb as it sounds) is to fill until fluid starts coming out. Plug it up and away you go. Transmission fluid should be fine through >100K miles...
I have yet to do mine... I'll be sure to send a sample for testing... (great, now I have to find THAT post. Rather slow on an iPhone)
You might take a look at this and determine for yourself the merits of an early fluid change. I'm a believer. Based on numerous analysis results, WS fluid doesn't last anything close to 100,000 miles, in either a Gen II or a Gen III car.
Just to update everyone, Eneos has just released a new ECO-ATF, which meets Toyota WS: ENEOS has introduced its next generation Automatic Transmission Fluid, the ECO-ATF. ENEOS ECO-ATF is an ultra-low viscosity "multi-vehicle" transmission fluid that is compatible with ALL Japanese vehicles equipped with an automatic transmission (excluding a CVT transmission). This includes Toyota's WS (World Standard) transmission fluid.
I am assuming you mean a 2010 Prius? If you have not changed the fluid on your 2004 it's only $60 at the dealer or any competent mechanic can do it. It is too bad that it is not in the maintenance schedule for normal service, no fluid is good forever.
I changed my transmission fluid today and it was definitely in need. Old compared to new fluid color was unbelievable. At any rate, something happened that suprised me and I'm wondering if this is normal. When I loosened the fill plug first, it released some pressure through the release of air which I could hear hissing. I was not expecting this, but wondered if this was normal.
What was the mileage on the odometer? When I did ours at 30K and 90K there was no detectable pressure release as you described.
