Transmission/Transaxle Fluid Replacement ?

Some time after production ended, as a replacement part. The old version is no longer available.

No. The pump is not readily accessible, so a distinguishing mark wouldn't be of much help anyway.

No.

 

Actually pumps are available from salvage yards. This is why it is important to know the distinguishing markings that might show the change. For example, there was an NHW20 change:
Luscious Garage | Blog | Prius Code P0A93: Inverter Water Pump Failure

However, Lucious doesn't mention an NHW11 pump change:
Luscious Garage | Blog | Gen 1 Prius code P3130: Inverter System Cooling Malfunction

Hobbit has some good hints on the NHW20 pump:
Inverter Pump

Everyone else, next time you're in TIS, see if you can find anything about a change in the NHW11 inverter pump between 2001-03. In particular, look for a part number or other identifier.

I checked the usual sources and the only thing interesting:
Yahoo! Groups

Bob Wilson

 

Again, the pump is not easily accessed. Salvage yards typically require do-it-yourselfers to remove the part themselves. This requires removal of either the inverter, or the front bumper and one headlight.

TIS is not a parts catalog.

 

Would you care to share with us the info source that you used to determine that the inverter pump design changed, if not TIS?

 

I didn't say the source wasn't TIS. I said that TIS is not a parts catalog.

You cannot depend on running parts number changes to be disclosed in TIS. Nor will a local dealer's parts database always be able to access the old numbers, particularly if the number change has taken place some time ago. In this case, the source is my own experience; I remember the redesign taking place a few years back.

If you do search TIS for the part number, don't search the RM. You'll only find a parts number change in a TSB, and only then if one is associated with the redesign. At any rate, the redesigned pump is the only one available, and has been for some time. You don't have to worry about buying the wrong pump.

 

Not too bad for a first oil change. You can see the magnet looks like a 'slug' and that is the magnetic material. Past oil analysis suggest 3x of nonmagnetic material in the oil.

The pale bits are transmission case sealant. It bleaches over time, losing the iron oxide pigmentation into ... the transaxle oil. Were you able to save an oil sample?

The reason I ask is you may want to treat this as an initial flush and change it again in the Fall. Two samples at a fixed distance and we can do a partial fractions analysis to figure out how much is carry-forward. I've done it once and have no problem with independent metrics.

Bob Wilson

 

Your fluid has quite likely been changed before. 45K fluid from a healthy transaxle can look worse. The amount of ferrous material on the magnet and debris in the pan is lower than normal.

Yours looks fine. Fluid plays a factor in transaxle failure when it is significantly degraded. Gen 1 transaxle failures are rapid and cannot be reliably predicted by fluid analysis.

Just change your fluid every 60K, and you'll be doing all that you can do. You don't need to drop the pan unless you want to, now that you know that it's relatively clean, and the screen is clear.

 

I agree with the part about cleaning the input screen. I've seen some that are so clogged up when you wipe them fluid drop out of the tube which means tranny had reduced oil flow and all kinds of potential damage can occur.

You must drop the pan on Gen1's to properly clean things.
Gen1 Prius Transaxle Service

For those of you complaining about $6-$9 per quart fluid just relax and pay the dealer....it's still a thousands of $$ cheaper and easier than replacing your entire transaxle....

I've replaced about a dozen Gen1 transaxles so far....some of which I'm sure could have been avoided with proper servicing every 30k miles.

Lastly, the dealer DOES NOT normally drop the pan when changing Gen1 fluid. Insist they drop the pan and clean everything if you have them do the job.

 

Excellent link!

I suspect the 'crud' is from case sealant. Have you or your customers done any oil analysis?

Stator coil shorts? Any mechanical failures?

I always have to order my gasket from the parts department. They never have them in-stock.

Well you've reminded me that this weekend is transaxle and engine oil change. I've been running Type WS instead of Type T-IV for ~33k miles and will send a sample for analysis.

Have any of your customers considered running Type WS instead of Type T-IV?

Thanks, great posting,
Bob Wilson

 

This was very helpful, since I had not changed the transmission fluid myself before, but I'm curious, this article says you should replace 4.9 quarts atf, while other sources (including the dealership) say 4 quarts even.

Is there a consensus? Or is it safe to do it the old fashioned way and fill it with the car level, until a little drips from the fill hole?

 

It is 4.8-4.9 quarts and that is exactly the procedure I used last weekend. I had 5 quarts and it started dripping just at the end of the last quart. I had already emptied my catch pan and replaced it to catch the drips.

I had a dry, water bottle and used it capture an oil sample for testing. I should have the results this week. Experimentally, I'm using Type WS but that is based upon a couple of years of oil analysis.

Bob Wilson

 

The 2G requires 4 US quarts of Toyota ATF WS. The Classic requires ~5 US quarts of Toyota ATF T-IV. It is fine to fill the case until you start to see the new fluid ooze out of the fill hole.

 

Great write up but I have a few questions.

1) I assume it's better to have the fluid fully warmed up?

2) When filling, does the car have to be level? I would drive the front up on ramps so it would be 8 inches higher.

3) The picture shows you filling from the top. I thought the fill plug was just above the pan and reached from under the car?

4) To clean the pickup screen can you just spray it with brake cleaner? There is no mention as to how specifically it's cleaned.

 

There is one place that continues to irk and that is the area under the differential gear. I have no doubt that debris there is picked up and cycled through the gears to make the 'liquid smoked.' Sad to say, I've never figured out how to suction out that basin.

If you find the oil especially bad, you might want to run say 5-7,000 miles, say a nice day in Spring, and do it again. Treat the first change as a 'flush' and the second one is for real.

Bob Wilson

 

Thanks, I'll be using this filler to make it easier though.

 

What does anyone think about just adding the whole 5qts while it's jacked up?
That way there will be no spillage, and no wasted new oil, and it will definitely be full (slightly over full) when you let it down. At .1qt over full I doubt it will harm anything and probably even better, as long as all seals are good.
It's been my experience that when it comes to tranny gears etc., too little is much worse than slightly too much, but way too much is also bad (as the dealer does to the ICE!) I wouldn't be surprised if one let the dealer do the tranny oil that they just dump the whole 5qts in as well.
With no dipstick to check it who would?

 

I agree that 0.1 qt is not enough to worry about.

The dealer tech will typically raise up the car on the lift and fill until fluid starts to ooze out of the fill hole. That is the correct amount to add.

A DIYer can do the same by raising the car on 4 jackstands so that the car is level. If that is too much trouble for you, then raise the front on 2 jackstands and fill with 5 US quarts.