openinverter forum

Hi All,

I recently tested the control of the oil pump on my 450h transmission, and it sounds really loud when it runs. I can also hear the oil sloshing around, so it might technically be working. I am using Damien's VCU, and it sounds loud across a range of PWM duty cycles. I am guessing it shouldn't sounds like this. Any thoughts? See the video below, any help would be appreciated.

Is the transmission filled with fluid? Sounds like it's running dry.

Hmmmmm, wow, I guess I didn't check. I could hear fluid moving around in there, but I didn't check if it was filled. What kind of oil should I fill it with?

The fluid for this transmission is Toyota WS (world standard), there should be plenty of alternatives available.

The pump sounds like it is running dry.

There were bearing issues with these pumps, it may be worth opening yours up to check the condition of the bearings.

Doesn't sound like it's "chirping", I'd wager on the pump running dry.

Sounds dry to me, could also be cavitation if it’s cold and you’re running it at high speed.

Incidentally, I logged on to post a similar question to the forum. With new transmission fluid fully filled, I hear what sounds like cavitation above about 40-45% duty, depending on ambient temp (~60F). This tells me that running at 50% on a cold transmission is likely to actually destroy the pump. Running at 30% duty now and I’m not hearing any tell tale signs of cavitation.

Have you filled it properly?

The fill procedure requires the engine to be running - this is done with the car in "maintenance mode", which makes the engine "idle" at 1000RPM, which drives the primary oil pump (the electric one is auxiliary - runs primarily when the engine is off and to provide additional pressure when shifting). Oil temperature must be between 30 and 40 in order to measure via the "drip" hole.

So I went ahead and changed the oil on the transmission (drained out old oil and filled with about 5.5 quarts). After that I tried a few different duty cycles (10, 20, 50, 80) and I still think it sounds loud. 20 definitely sounds the quietest, but how do I know if appropriate oil pressure is being generated? See video of the tests here:

Bryson wrote: ↑Tue Aug 03, 2021 5:44 pm Sounds dry to me, could also be cavitation if it’s cold and you’re running it at high speed.

Incidentally, I logged on to post a similar question to the forum. With new transmission fluid fully filled, I hear what sounds like cavitation above about 40-45% duty, depending on ambient temp (~60F). This tells me that running at 50% on a cold transmission is likely to actually destroy the pump. Running at 30% duty now and I’m not hearing any tell tale signs of cavitation.

Thanks for the info! I think I just might do the same. I posted a video where it was running at 20%, did yours sounds similar?

Mine is smooth at low duty, no cyclical noises like yours. Could be bearings too, I’d take the pump apart and replace them. Does not sound good in that video!

Bryson wrote: ↑Mon Aug 09, 2021 2:57 pm Mine is smooth at low duty, no cyclical noises like yours. Could be bearings too, I’d take the pump apart and replace them. Does not sound good in that video!

Dang.... Yeah I think I just might do that. A while ago I noticed someone post a step by step on how to replace the bearing, did anyone have a link to that? Can't seem to find it.

bobbyj_408 wrote: ↑Mon Aug 09, 2021 9:58 pm

Bryson wrote: ↑Mon Aug 09, 2021 2:57 pm Mine is smooth at low duty, no cyclical noises like yours. Could be bearings too, I’d take the pump apart and replace them. Does not sound good in that video!

Dang.... Yeah I think I just might do that. A while ago I noticed someone post a step by step on how to replace the bearing, did anyone have a link to that? Can't seem to find it.

It's in the WiKi here: https://openinverter.org/wiki/Lexus_GS450h_Inverter
Here is the direct link to the guide: https://carlthomas66.blogspot.com/2016/ ... -pump.html

I'd like to test the oil pump on my 450h motor whilst waiting for the zombie board to turn up. How did you test yours? I'd like to make a standalone test box just for this purpose. I'd look to use an Arduino with a mosfet driver circuit.
What do you suggest?
Thanks

Yesterday I did check oil level first time, maybe surface was not perfectly flat, but there was more oil than there should be. This gearbox did not have oil cooler and oil cooler plugs seems to be original. Oil smelled burned, reason could be slippage what I have noticed during testing different oil pump speeds. Will get new oil and replace.

Reason why I checked oil level is that oil pump motor sounds healthy, replaced bearings before installing to car, but unevenly it sound like pump does not get oil or there is bubbles. Is this normal or should it sound very regular? Its not loud but noticeable, I was thinking too low oil level.