A couple of days ago, I happened to be catch a ride with someone who previously had a 3rd gen RX450h but had just bought a brand spanking new (Australian market) 4th gen RX450h. When I looked through his service booklet, the additional maintenance section also specifies replacing the fluid at 75,000 kms.

So at least it's consistent with the 4th Gen as well.

 

Looking at a used 2010 with 100k miles on the clock. The only issue is no service history on the differentials or transfer case -- how concerned should I be?

 

Have none of these conditions like I bet most of us also do not. I will listen to my local Lexus Service Manager who has more experience than anyone on this forum. He has been trained by Lexus to work on Lexus's all day. When asked he said it does not have to be changed and the changing can do way more harm than good. Hilarious here reading post after post how the dealerships just want our money. Here they do not and now they do not believe them.

 

I think its a "to each their own" scenario here. Those who are comfortable with following Lexus advise don't need to anything. Simple! The ATF is there for splash lubrication only anyway. It goes black from being over heated from certain driving conditiions, but I suspect the planetary gear seat won't mind burnt oil so much as a conventional automatic gearbox (e.g. RX350) which needs the protection of the fluid for the multiple clutch packs. And anyway, many of you may not even be stressing the oil to the point where it gets burnt, so the fluid can be kept in service for an extremely long period of time, way past warranty period, so Lexus is off the hook for any warranty claims.

Those of you RX450 owners who want to change the fluid, by all means get it done, but change it at your own risk. Replacing fluid has a risk of introducing contaminants into the hybrid transaxle. Trying to do good can end up in something bad happening, which is probably Lexus' thinking.

The perogative to change or not to change the fluid is entirely up to each owner. After all, it's your car, maintain it however way you see fit.

 

Its now been 8 years and 80,000 kms since I first did a transmission fluid change to the RX450h.

The front fluid (which was changed back in 2018) is now visibly darkened. But no burnt smell. I think it *could* benefit from the change, since its darkened. Anyway, the job was quite easy to do, so I probably would next change it if I keep the car for another 8 years.






I decided to change the rear fluid as well. It has never been touched since I read posts from this forum that the rear differential fluid tends to be in good condition, so its never been touched before.

In other words, its the original factory fill when the car was made in Japan back in 2013, i.e. its thirteen year old fluid which has travelled 125,000 kms.

I was expecting it to be dark too, but when I opened it, the colour of the fluid looked exactly like brand new fluid.




So from what I now know about my 2012 RX450h is that the rear diff fluid can be absolutely treated as "lifetime" fluid. I will never ever touch it again, unless there was a reason to.

But the front transaxle is a different matter - I will change the fluid again, but perhaps in another 100,000 kms (or 60,000 miles).

Thanks for reading. Sorry for the extra large photos. Can't figure out a way to resize them with the IMGUR platform. :-(

 

limiting to 450H transmission ..

Just like rear diff the transmission is just a set of gears where the fluid is for lubrication. Only other thing is activation of some motion based on fluid pressure directed by valves.
What the fluid gathers are the metal shavings that need to be captured by the filter.

All the above is very different from 350 auto-trans.

Personally I am on 60k interval for my FWD.

Salim

 

The missus said that the car drives much nicer than before, feeling smoother and more refined. She asked me what I did to it. So I told her that I did a transmission fluid change.

That's all the evidence that I need that fresh fluid does absolutely makes a difference. The wife is NOT a car person, yet she could tell something had changed.

I had personally thought that it was a placebo effect when I drove the car after the fluid change, but now I have confirmation it wasn't my mind subconsciously finding a way to justify the effort and expense taken to change out the fluid. Happy days.

 

How many quart of the ATF-WS did you use for the front fluid?

 

https://www.clublexus.com/forums/hyb...diy-index.html

There are a few video on the net as well.

Salim

 

I didn't measure exactly but it was slightly over 5 quarts.

There are actually two possible places to fill the transmission when you take off the left front wheel. One plug is higher up on the left of the CV drive shaft sitting higher up and slightly obscured by the plastic wheel well arch (removable trim piece there), and the other is directly to the right of the CV output shaft, on the same level. This opening is actually the fluid levelling port - where the transmission fluid stops dribbling out when the warmed up fluid is at the right level.

I just filled up the fluid on the right side till it started to dribble out.

ATF fluid expands its volume significantly when warmed up, so the idea is that the plug on the right side serves as a level for the fluid when it is warm. But I didn't bother to warm up the fluid by driving around and then draining the excess. That's because the eCVT gearbox isn't so sensitive to fluid levels, compared to a conventional automatic gearbox that has clutch packs and shift solenoids, where fluid levels are much more critical to get right.

So technically I should have filled up to till the fluid dribbles out of that port. Closed it lightly, gone for a drive to warm up the fluid and reopen it to let the excess fluid come out so that its level. But I didn't bother to do that - I did the fluid change exactly like how I did it 8 years ago and did not have a single issue with the gearbox.

But if you follow the procedure properly it will be the right thing to do instead of taking a short cut like I did.

 

Thank you... I appreciate the information... very helpful!