Transmission fluid change

Mihanicos · June 29, 2017

Hi everybody, my car is due for a transmission fluid change and I cannot find the filler plug. I looked everywhere except on the top of the transmission which is impossible from underneath the car. The Lexus Techdoc suggests to disconnect a small rubber hose about one foot from the gearbox on the fluid line to the oil cooler and fill the transmission from there.

There has to be a fluid filler plug because without that, the fluid level cannot be adjusted if its temperature is not within the 30 C to 40 C range. A special tools is connected to the filler plug to to add fluid or apply vacuum so no fluid drains from the pan when the drain plug is removed in order to connect to it another special tool which compensates for the fluid level at higher temperatures.

Hangie · July 9, 2017

There is no easy fill plug.

ive asked lexus garage to change it in mine and they done it without problem but I don't know exactly how.

Mihanicos · July 9, 2017

Dear Hangie,

Thank you very much for reply.

I changed the transmission fluid myself according to the guidelines in the relevant Techdoc publication. It was not difficult but if you need to add fluid, you have to disconnect the rubber hose connecting the oil pipe to the oil cooler, adjacent to the gearbox. Had it been a filler plug available like in other models, you simply add fluid at a temperature between 30 C and 40 C it trickles from the drain plug.

In the Techdoc publication it is over stressed in every step of the guidelines in red letters to make sure that you have no line pressure in the fluid filling process. I had had no line pressure DTC so everything was ok.

To do this job you need the Techstream.

Kindest regards,

Chris.

Hangie · July 11, 2017

Yes I know techstream - that why a gave it to lexus garage :) it is still very rare maitanance so I can pay.

in general I think it was just over £150 with oil.

alexchrisro · July 16, 2017

Did you feel anything after changing the oil? Did the old oil look black and dirty? I asked my stealer of changing the gearbox oil for my gs450h and they said it is life time and it does not need changing... allso from what i'v read it is imposibile to change all the oil in the gearbox because it is sealed...

steve2006 · July 16, 2017

How is "lifetime" applied? What exactly is the expected lifetime of any vehicle, I couldn't see my 1994 LS400 transmission being very happy with an ongoing fluid lifetime of 23 years hence why it has been changed twice during my ownership.

Mihanicos · July 17, 2017

In the owner's manual it is stated that the gearbox is sealed and the fluid is intended to last the car's expected lifetime.

However, if you look up the maintenance and service schedule in the Lexus Techdoc, depending on the region the car is being driven, you will find all the relevant details. In my case, it needs a transmission fluid change every 72 months or 70 000 Km ( I am not quite sure about the Km but it is not far off there ).

I had 42 000 miles on the clock and the oil that came out began to change colour, pale red. I also found out that it had less oil than the right amount, somebody attempted to check the fluid level without first circulating the fluid through all the gears and probably at a higher temperature than 40C. The 5mm allen key plug which is removed to check the fluid level was very tight whereas the 14mm drain plug was at specified torque. This a clear indication of what had happened.

Now with the correct amount of new transmission fluid it operates like before and when braking down hills, all the gears hold the car very well with constant braking, the position of needle of the Kw meter remains constant in the blue range corresponding to each gear being used.

Bear in mind that in an ecvt hybrid gearbox the electric motors MG1 and MG2 generate a lot of heat when in traction or generating mode. The transmission fluid is intended to cool them and lubricate the bearings. Channels and pipes within the gearbox make sure that the windings of the motors get a constant supply of oil to cool them.

Kindest regards,

Chris.

alexchrisro · July 18, 2017

Thank you for your answer, another question, i found a local shop that is maintaining toyota and Lexus, They said that this gearbox has a filter and it is my choice if i want that filter to be changed or not. Is this true?

Thank you

Verbout · July 18, 2017

What, that you have a choice? :)

alexchrisro · July 18, 2017

Mmm no, not really, i was more curious about the transmission filter... :)

Hangie · July 19, 2017

Filter is probably inside like in the ZF transmission.

if so you would need to remove the oil pan which more work and parts.

ive changed my transmission oil at 90k miles and schedule next for 150 if I'll still own the car. My was done by Lexus dealer. They are happy to do it even it is lifetime / warranty time :)

Mihanicos · July 20, 2017

This ecvt gearbox has a filter in it and it is made of a fine steel mesh. Given that the owner's manual states that the transmission fluid needs no change and the Techdoc maintenance schedule calls for transmission fluid change only and not the filter as well, then this should suffice.

I have another Toyota with automatic transmission and I changed the filter as well as the fluid. I bought the filter before I removed the transmission pan and both were made of a fine steel mesh, exactly like the one for Lexus. The car had done 150 000 Km and the filter was clean and there was no difference between the new one and the old one. I put the new one in and there is no difference in the transmission performance.

With this in mind, I opted out not to change the filter on the Lexus for now. The ecvt transmission is not like a conventional automatic transmission with clutches.

Regards,

Chris.

alexchrisro · July 20, 2017

Thank you very much for your answers guys!

Britprius · July 23, 2017

On 7/20/2017 at 8:41 PM, Mihanicos said:

This ecvt gearbox has a filter in it and it is made of a fine steel mesh. Given that the owner's manual states that the transmission fluid needs no change and the Techdoc maintenance schedule calls for transmission fluid change only and not the filter as well, then this should suffice.

I have another Toyota with automatic transmission and I changed the filter as well as the fluid. I bought the filter before I removed the transmission pan and both were made of a fine steel mesh, exactly like the one for Lexus. The car had done 150 000 Km and the filter was clean and there was no difference between the new one and the old one. I put the new one in and there is no difference in the transmission performance.

With this in mind, I opted out not to change the filter on the Lexus for now. The ecvt transmission is not like a conventional automatic transmission with clutches.

Regards,

Chris.

The GS450H does have one clutch within the transmission. This is operated by the external electrically driven oil pump, and operated at around 60 mph to reduce the RPM of the electric motor generator MG2.

John.