2001 Prius HV Transaxle Coolant Replacement

there should only be one drain plug... which two did you open? or are you thinking of the two bleeder screws up on top?

there is another drain plug nearby- the coolant plug is 24 mm bolt and screwed into the bottom of the aluminum of the transaxle housing. the transmission plug is a 10mm allen nut, and is in the black metal pan of the transmission, just off to the driver's side. this plug is for draining transmission fluid. there is another 24 mm bolt roughly halfway between those 2, toward the radiator, that is the input for transmission fill.

transmission fluid requires a special apparatus to fill. i hope you didn't drain that stuff too.

at this point, you've blown air into all the inverter lines at this point. drive it down the block, top it off. drive it down the block, top it off. keep on until it's full. DO NOT drive it far. drain and fill of that system is a real pain and you can't use the bleeder valves anymore with all that air in the lines.

 

wait a sec, even on the Classics the transaxle coolant and the
inverter coolant are the same, aren't they? Sounds like you drained
the coolant *and* the transmission lubricant -- they're both pink,
but different consistencies ... but if you refill both those volumes
with the same thing, you will be *really* hosed.
.
_H*

 

<div class='quotetop'>QUOTE(statultra @ May 31 2006, 08:52 PM) [snapback]263720[/snapback]</div>

oof. yeah that's what we were afraid of.

there might not be a pan on the 01, but the concept is the same. you drained both. hopefully it'll end up okay. you have to fill the trans fluid from the front of the transaxle housing. the inverter coolant is filled from the reservoir in the center of the motor on the top, next to the air filter. not to be confused with engine coolant, which has its own separate pressure cap and reservoir.

be absolutely sure the transaxle has fluid before trying to fill the inverter coolant reservoir! the only way you're filling that inverter res is by driving it around to flush all the air out of those lines by driving it. you don't want to drive it without trans fluid.


transaxle coolant= inverter coolant.

transaxle fluid is oil, not coolant.

 

<div class='quotetop'>QUOTE(statultra @ Jun 1 2006, 07:03 PM) [snapback]264305[/snapback]</div>

yep

also yes

correct- it is a sealed area.

good luck oh- and have fun getting all the air out of that storage tank...! remember, there's an air bleeder on the side of the radiator. may also be one on the coolant tank... don't recall offhand.

 

Hi Brian,

<div class='quotetop'>QUOTE(statultra @ Jun 1 2006, 06:03 PM) [snapback]264305[/snapback]</div>

I'm sorry I didn't see your first post. I don't hang out in PriusChat much. I've been making a study of Prius transaxle oil:

http://hiwaay.net/~bzwilson/prius/pri_T_cold.html
http://hiwaay.net/~bzwilson/prius/pri_toil.html

My study has been just the NHW11 models, not the NHW20s.

It sounds like you didn't drop the pan on this NHW11 transmission oil change. I'd recommend that after 10-15k mi., you treat this change as a 'flush'. Go ahead and get a new transmission pan gasket and "o" ring early and have them ready (lead time on the "o" ring.) When 10-15 k mi. have passed, drain and wipe down the pan, leaving the magnet, clean out the oil pickup tube and wipe down all exposed surfaces. The Type T-IV should be at the viscosity limit then and you'll have collected most of the remaining gunk in the pan and the gallery located to the rear. If you can, use the washer pump to drain that gallery and using a coat-hanger tool, wipe it out too.

Bob Wilson

 

Any suggestions on

Any thoughts on flushing the transmission fluid out of the inverter coolant system due to operator topping the fluids off incorrectly. My idea is to disconnect components and use air and denatured alcohol to flush everything out, like flushing an A/C system. Then, filling with water to see what floats to the top and flushing again if needed. Just wondering if this would damage anything by lack of foresight on my part.

 

By the way, we're talking about a 1st gen car. It was driven after the oil was put in the coolant system.

 

We are probably talking about a few ounces of transmission ATF mixed with ~2 quarts of antifreeze. I suggest that you start by draining the fluid and refilling just with water, then purge the air out of the inverter coolant system (which is not easy, BTW, on Classic Prius) to restore fluid circulation.

Then drain the water and see what residue remains within. May have to repeat this a few times...

I would avoid using alcohol in the flush, unless the oil residue proves to be persistent.