Not wanting to be left out, I finally had my CVT fluid and rear differential fluid changed for the first time too after 206,000km/128,000mi. My RXh is 10 yrs old this Monday so I guess it deserved a little birthday present. I chose the sitting on the couch method instead of the crawling underneath method. I'm kind of curious to see if it would have any effect whatsoever on fuel economy. I've been having a really good summer this year in that regard, this current tank was floating between 7.0 and 7.1 (between 33 and 34mpg) before the mechanic's test drives pushed it to 7.3. I don't really expect to notice anything, but I'll be paying a bit closer attention.

 

Finally got mine done, 13 with 120k kms. The fluid looked brown. Took about 3.7L of ws fluid for the front.

 

I'll sum up this thread
1. before 2012 both fill and drain plugs are on the same side; after 2012, fill plug is on the wheel side and is best accessed with wheel removed and removed with a short stubby L shaped 10mm wrench and cheat pipe
2. ATF in PSD is splash lubricant and bears no hydraulic function. hence, it might as well run lifetime. That it darkened means little. I personally am aware of a guy who 270 000 miles on original fluid and no issues,.
3. there is no transfer case or driveshaft as rear wheel drive is purely electric, via small edition of PSD.
4. heat into ATF may be produced by motor generators inside PSD, but MGs are cooled by inverter coolant, not ATF in PSD

 

Here was my experience today on a 2013 RX450h w/tow package 100K miles.

Some stuff is repeated but I think it sometimes helps to get confirmation.

I did both front and rear. I started with rear and used 4 jack stands plus the jack for backup. Note technically both the front and the rear are transaxles not transmissions or differentials That helps I think explain the AFT fluid for those that are still confused why a rear diff could use ATF. I know, it's got the electric motor but even so I was confused until I saw the entire assembly.

Fluid:
Toyota ATF WS (World Standard). Bought 7 quarts, used 6 and a bit. Bought from Toyota dealership, didn't mess with substitutes. Car was jacked up as levelish as I could get it with 4 jack stands.

Tools:
1) For filling I used the Harbor Freight multi transfer pump. This works well with a helper. The multiuse pump tends to get messy toward the bottom of the bottle as it throws out air and fluid. It's not fun doing it by yourself as the hose wants to hop out of the bottle or knock the bottle over and you gotta keep the other hose in the filler hole and pump all at the same time. Even with a helper it left a mess at times.
2) 10mm hex socket + 3/8" ratchet (too big for front filler). See if I had to do it all over again notes below. I ended up monkeying wit the socket + 10mm wrench + 23mm wrench as cheater pipe for the front filler to crack.
3) A good sized fluid catch basis meant for coolant I found on amazon

Rear:
10mm Hex for both Filler and Drain which are on the same side. They point to the drivers side. Breaking the hex loose on the filler plug was significantly harder than the drain plug. About 2x the effort. I used a ratchet with hex socket attachment. I think a hex key with cheater would have been just fine too. Spacing with the 3/8" ratchet was not an issue. When I tried to do the 1/2" breaker bar + 3/8" adapter + hex socket that was too wide to fit with the filler. The rear drain also has a magnet and there was a bit of stuff on it but not much. I cleaned it off well with a shop blue paper towel then went overboard and sprayed some engine cleaner on it to get last stubborn little pieces. I did coat the plug and washer a little in ATF after.

Front:
10mm Hex for both plugs again. Drain plug is facing the passenger side while the filler plug is facing the driver side. The youtube video of the guy and his son is accurate. I did not go through the tire well. Drain plug is straight forward with good access. Filler plug is where the youtube video has it too. Note it is NOT on the same side as the drain plug. Slide over toward the driver's side wheel on the other side and look up. It's a tight space. I managed with my 10mm hex socket + using a wrench to turn it but would have been much faster with a properly sized allen wrench and cheater type pipe instead. Like the rear the filler plug is about 2x the effort of the drain plug.

Oddity on the Front: There's another filler plug above drain plug above the cv axle. Like others, I have no idea what it does and I also tried to fill from here initially but there's only about 2mm of ability to put a hose in. Result = fluid all over especially by myself with the HF pump. There's also another drain plug that's oriented vertically on a plate very near the real drain plug. No idea what that does either! No one else has mentioned that one. So in any case, on the front you want to make sure to identify the proper filler and drain first. The ones that appear to be correct are the ones the manual says they are. I really would like to know more about the two other mystery plugs though.

Stuff I didn't do
"FWD inspection mode" I have techstream but didn't bother. Just took it for a drive. Seemed great.
Recheck fluid after driving. I filled until it poured out, waited a bit filled a bit more and poured out again.

How was the fluid
I did not send any for analysis so this is a who knows. Rear was redder than Front. Rear had some debris on magnet. Front drain plug didn't have a magnet. Is it lifetime? Hard to say. Was it sludge? No not at all. Burnt, no not at all. Worth changing, probably if your a bit mechanically inclined. I could see it last 150, 200, or 250K miles. Your mileage will vary.

If I had to do it all over again:
1) The rear worked fine as described but a allen wrench with cheater pipe would have made cracking the filler much easier.
2) For the front the same allen wrench and pipe would have made the job much much faster.
I don't have any good way to suggest what sized hex tool will work best across the board. Unfortunately you gotta kinda climb under there and see for yourself then hit up the stores. What size you can use for a ratchet, hex key, or cheater bar also will depend on how high you can jack the car. I think 15" or so would have been ideal for the leverage and I'll do some combination of hex key and cheater piper next time for that.
3) ID the filler correctly for the front
4) Get a helper right off the bat for using the transfer pump. The youtube video shows an alternate technique for the front but that requires taking the front tire off.

Hope this helps someone! I was intimidated but did it and learned a bunch! Good luck.

 

Not sure, what is there to look up for the plugs wrench. It is 10mm L shaped hex, or Allen wrench. Short end needs to be shaved down to a showrt stub, just enough to firmly be inserted into the plug and allow for cheat pipe on it. Been a while, I think, anything more protruding out is rather not feasible for the front, if plug is on the wheel side. Taking wheel off definitely helps and, having finger on the wrench, firmly pressing it into the plug, is crucial.
ALWAYS UNDO FILL PLUG FIRST. Always. You can easily tie funnel to hood strut and run filler tube down to the filler hole, to use gravity feed from the top. No need to turn this into teamwork, unless you just need excuse for wife to have beers after.

 

The funnel top to bottom sounds interesting, I'll need to try that, thanks! Of course laying underneath I can't see any light from the top and looking from the top I can't see the floor in any way shape or form. Heck I can't even find the inverter coolant plug drain, I'll need to search and post about that next.

Guestimating here form a few days ago but to me it seemed about 2" that you had to work with and there was some taper from maybe an engine mount or other frame type piece. Allen plus cheater pipe would be my approach in doing it again or finding a much shorter hex socket. Mine is about 1.5" so not enough room with the bigger ratchet I had. Of course now that it's off for the first time I also didn't torque it back down like the factory had it and put a tiny bit of of ATF on the threads to help with that.

 

Easiest is a long tube with a funnel on one end and the other end inserted int he fill hole. You can stand by the wheel and pour in fresh fluid. The fluid that is left int he tube [you can raise the fill end] is wanted, so buy a tube of smaller dial. The trade off you make is the fill time vs lost volume. Larger did will transfer the fluid quicker..

Salim

 

1/25/23 If I simply remove the transmission drain plug in my 2015 Lexus 450H, without doing any other kind of flush, how much transmission fluid will come out? 2 Quarts , 3 Quarts , etc ??? Thanks

 

It will overflow if try to overfill.

See segan's post #36 in this thread for number of quarts.

Ask the parts counter person at time of purchase and confirm that they will take back any un opened bottle.

Salim

 

OMG I've been trying to figure out why I've been having "Hybrid System Overheat" happen sometimes on a long highway drives and this may very likely be it! When I bought the car I had the transmission fluid changed by non-hybrid mechanic and I remember him telling me the car took more transmission fluid than what was stated by the manufacturer. He must have filled the gear box! I always thought it was a weird coincidence that I got these overheating issue after the transmission fluid change. What should I do now? Do I need to get the transmission fluid changed again (by a different mechanic) or can I just have the mechanic let some fluid out?

 

Just open the fill plug and the excess fluid will drain out. The fill plug is positioned such that it is the max level for the transmission fluid, which was what Salim was saying above.

I find it hard to believe that its possible for a mechanic to overfill the transmission, as the excess will just rush out of the fill plug when the mechanic is trying to reinstate the plug. Any good mechanic would know not to intentionally overfill the transmission beyond the fill plug.

My thoughts are that the fluid may not be the correct spec, i.e. 3rd party fluid, and somehow this fluid is causing the overheat condition.

 

Nick682 talked about some models having another fill plug on the very top of the gearbox. If that's what this mechanic used then he may have put there too much. I do find it suspicious that he told me he fit in there way more than it was stated by the manufacturer. He did use the recommended fluid, that much I know for sure. I'll start with what you recommend and will open the fill plug to see if anything extra comes out. Fingers crossed it's that simple of a fix to my issue.

 

Lexus recommends their transmission fluid instead of gear oil. Transmission fluid expands a whole lot with temperature. So please make sure you fill and let it drip out around 70-80F range. In other words don't do he level check in very cold or very hot.

For the purist, fill and warm up the transmission to a certain temperature [see the spec somewhere] and then remove the filler to allow the fluid to drain off or add some as needed.

Salim

 

Thank you!!! I've been dealing with Hybrid Overheat issue on my 2012 rx450h for over a year after a transmission fluid change. Your mention of the connection between those two helped me to finally solve it. Got the transmission fluid checked and sure enough there was lot of extra pouring out of the fill plug. The car now runs better, has better mpg and no more Hybrid Overheat! That was it!

 

Thanks for the great info everyone.

What size tube would you recommend to properly fit in the fill hole?

Thank you./