Whats the consensus on changing CVT fluid

<div class='quotetop'>QUOTE(Muleears @ Jul 5 2006, 01:03 PM) [snapback]281523[/snapback]</div>

We don't really have a 'voting' mechanism but I'll share what little I've learned:

- at least two independent Prius maintenance shops are following a 30,000 mile change
- the NHW11 (classic) uses Type T oil
- http://hiwaay.net/~bzwilson/prius/pri_T_cold.html
- http://hiwaay.net/~bzwilson/prius/pri_toil.html

IMHO, you need to change the oil including dropping the pan and having all interior surfaces cleaned. Be sure the magnet is returned. To do it right, you'll need a $9 transaxle gasket and $3 "o" ring. Also, make sure the gallery to the rear is pumped out and wiped out (will need a 'coat hanger' tool.)

I would recommend getting a sample, ~100 ml., in a clean, dry polyethelyne (urine sample container) or polycarbonate (water bottle). I already have enough samples at 60,000 miles but I'd recommend you evaluate the sample yourself and decide if you want to send it to an oil testing service. Things to look for or test:

- does it smell like paraffin or burnt?
- oil testing should test viscosity at 40 ( C) and 100 ( C) to determine how worn out it is
- judgement call, have particulate analysis, your call

You also have inverter coolant that needs to be changed. The consensus in Prius_Technical_Stuff is to use the 'pink' long life coolant. Bleeding the inverter coolant loop is a pain, multiple bleedings needed, but not that bad.

The most recent transaxle failure report was from Berkley CA and he reported the old oil was horrible and smelled burnt. However, I've had no luck getting a sample for testing. I understand he had over 100,000 miles on that transaxle and it took nearly 40 hours to replace.

Feel free to ask questions since we have a number of folks who have been there, done that.

BTW, I have one experimental change under test, replacing the transaxle vent plug with a breather hose to the air cleaner. This was due to the testing service reporting evidence of abrasive grit. However, not everyone is convenced it is necessary. I won't have definitive results until the current oil reaches 12-15,000 miles when I'll change and retest it.

Bob Wilson

 

Classic used Toyota Type T-4 fluid. Not as expensive as type WS either and is all you really need for a change. Like Bob said get a UOA on it, cheap insurance. Part number on the pan gasket is 35168-47010 and you'll need the drain and fill plug gaskets as well. If you do have the UOA done please post your results.

 

i have an 05 and bob bridge toyota told me it would cost $230 to do a change of the differential and cvt/psd/transmission? fluid. is that too much?

 

the WS fluid for a fill will cost about 50$ so that leaves $180 for about 1/2 hours work. You be the judge.

 

<div class='quotetop'>QUOTE(Muleears @ Jul 6 2006, 05:37 AM) [snapback]281893[/snapback]</div>

You'll need 4.9 quarts of Type T-IV. I'm conducting an experiment with Amsoil ATF but I won't claim any particular advantage.

The "coat hanger tool" is my attempt at humor. When I dropped the pan, I found a gallery to the rear of the car that I could barely get a finger in to test the presence of oil. I needed a pump or tube to drain the last of the oil but didn't have one handy. But the gallery surfaces will still need to be wiped down.

The "coat hanger tool" is a length about 14-16" long with one end bent back like a "U" hook about 0.5 inch. Then using a lint-free, cloth swatches, say 4"x4" T-shirt patches, squeeze the bent end to hold the swatch and bending as necessary, wipe down the surfaces until clean or cleaner. Avoid using painted coat hanger wire unless you brush off any paint flakes at the bends. It doesn't have to be perfect, just get as much of the gunk out as possible without spending a lot of time.

I suspect my 7,000 mile 'flush' would have come back much better had I dropped the pan and throughly cleaned out all of the gunk. My second change should come back with much better numbers once I get 12-15,000 miles on it. With luck, the viscosity loss will be just under 15% and the contaminants equal to or less than the 7,000 mile results. Regardless, we'll have a chance to compare the effect of dropping the pan and wiping down the pan surfaces.

Bob Wilson