greginwi

I have a 2008 Lexus RX360, 160k miles.

What is the general opinion on changing the transmission fluid? It is a sealed unit and says "lifetime fluid" but lifetime usually means 100K to the manufacturer.

BUT, I have heard that older transmissions might slip with fresh fluid if they are older and warm.

What have others done here and their result?

sunamer

a tranny will only be slipping if either it got wrong fluid, or it has been running on “lifetime fluid” for so long that it broke down the fluid, and wore out clutch material, which is now floating suspended in the fluid. Certified Toyota techs suggest changing it at 60k... One point - make sure you use authentic ATF WS (which is either toyota or aisin branded). NO OTHER MANUFACTURER produces compatible fluid, no matter what you hear here or in any other place. If some valvoline, or whoever, says on their bottles that it is compatible with toyota vehicles or atf ws - they are lying, as toyota does not license that fluid to others. period.

Seattle SCone

As a data point, my 224,000 mile SC430's transmission (albeit is an easy service 5 spd with dipstick) had it's fluid changed twice. The first time was around 100K by Lexus. The second was at 222K by myself with 6 fluid drain/fill cycles. The old fluid looked like coca cola and smelled strongly. No slippage post the change and gear shifts are now smoother and quicker.

If you are intending to keep your Lexus for more than 100K, chang the ATF fluid before it is too late.
If you are not going to keep it, don't change it. The "lifetime" is longer than your ownership and you can get away with leaving a problem for the next poor schmuck (and may Karma be swift for you doing so.)

sunamer

Forgot to add. I am yet to flush my 2015 is350 transmission (still below 50k miles), but several years ago, I did flush a tranny on my wife’s car - 2011 Corolla at 95.5k miles. Used ATF WS for that, and after the flush the shifts got noticeably quicker/more crisp. It is definitely worth it, and if your mileage is not more than 110-130k, and the fluid is just dark, but without smelling burnt or being like chocolate, I think you will be safe flushing it without getting any side effects

winterturb

In the US Lexus Manual says no change for the ISF tranny fluid. In Canada it’s different and says at 60,000 kms change the fluid. After taking to many mechanics that work in. Not only Toyota and Lexus but MB and BMW they ALL say drain and fill at 60k that’s kilometres.

it’s very easy to do. Just drain and fill on a cold transmission and put in exactly what you take out. Use only the fluid recommended in the manual. For Toyota Lexus use only Toyota labeled each fluid or whatever it calls for. Nothing else. If you do this you won’t ever have trouble with a transmission problem related to broke down or contaminated fluid. Sealed transmissions just mean they don’t have a dipstick. They still have a fill port in the side of the tranny that can be a little tricky to get to.

I have yet to hear any mechanic worth his salt to recommend a flush. That can cause more problems than it resolves.

there is a complex method of changing all the fluid by tying in to the cooling lines but you really need to know what you are doing to ensure you only put in what is taken out Over or under filling is not good.

I have 6 Lexus/Toyota cars with “sealed” transmissions and they all get regular drain and fill at 50-60,000 kms.