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Trans Fluid Change Interval


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The trans fluid dipstick on my 2003 lx470 says "atf fluid does not need to be replaced under normal driving conditions". Is this true?

No. I have mine replaced every 30K miles. The dealers here do a drain & fill at 15K/45K/75K miles, then a full fluid exchange at 30/60/90K, and that's with NO towing. The drain & fill every 15K is kind of excessive. I wouldn't go more than 60K mi on a pre '04 LX. The '04+ uses the WS type ATF which lasts 90K mi. You can run the type T-IV ATF much longer than 60K, but the problem is if you, say, run it 120K mi and then change the ATF, you're playing Russian roulette w/ your tranny, as deposits builds up inside the tranny from the old fluid, and then the new fluid breaks it loose, potentially damaging the tranny (know one guy who did this in a toyota celica...tranny failed a week after the ATF change).

I had the Toyota dealer do mine at 60K mi. Make sure they do a complete fluid exchange (not a "flush" with any flushing fluids). This is typically done by pulling the input and output hoses from the ATF cooler and plugging them into this big machine. The machine contains one large resevoir of new ATF (Takes like 16-18 qts to remove all the old ATF despite the total capacity of the tranny & pan being 12 qts), and one large empty resevoir. Then they start up the engine and let it idle. The transmission pulls in the new ATF from the machine while the old stuff (that would normally return to the cooler and then to the pan) goes into the empty resevoir.

FYI, a drain & fill is only 3 qts, so you still have 9 qts in the torque converter! Ask the service manager how they do the ATF change. I called a couple of lexus dealers and one guy couldn't tell me if it was a drain & fill or full transfusion. I took it to my local "award winning" toyota dealer and the SM happened to be an ex-tech. Not only that, bu t I lucked out in that the tech who worked on my LX was an ex-Lexus tech.

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  • 4 weeks later...

ATF loses its additives and effectiveness with time and wear; so consider the dipstick statement to equate to the warranty period.

On my 01 it says to "check" the ATF every 30K (vs. replace). My current approach is to drain and fill at about 15-30K with a synthetic ATF (Mobil 1, now with Redline D4ATF).

At least on your 03 you still have a dipstick for relative ease on doing a drain and fill. In 04 the trans went to a fill plug (like a diff or transaxle set up).

Depending on your milage, you may want to do the flush as Jim described, then proceed with the drain and fill.

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Since you have a '03, it should use the same Type T-IV as my 03 (it will say on the dipstick what type to use). FYI, Mobil does NOT make a synthetic type T-IV. FWIW, I'm told by a couple of sources that the Toyota brand type T-IV is synthetic. Lexus dealer charged $12.95/qt! The Amsoil ATF is supposedly type T-IV compatible. I'm sticking to Toyota's for now since (1) I have the dealer do the ATF exchange since I don't have one of those ATF machines and (2) the vehicle is under warranty until 100K, so if there's an issue w/ the tranny, they can't say it's damaged because I didn't use Toyota brand T-IV or that I didn't have it serviced properly. Also, the Amsoil isn't cheap, about $120 for a 2.5 gal container, and you need two 2.5 gal containers or $240 of ATF. Some dealers won't allow you to provide your own fluids/parts, some will and will just charge you labor, while some will but will still charge you the entire amount. Labor is 1 hr, so Amsoil would have cost me $350. Cost was ~$250 for a 12 qt exchange using Toyota T-IV. SM said they typically do a 8 qt exchange (so 2/3 of the ATF is new) to keep the costs down, but they then recommend an interim 15K drain & fill (3 qts). You save in labor if you have it done at 30K intervals with no interim drain & fill. Either that, or you do a drain & fill every oil change so that after 30K mi, you've finally replaced all the ATF.

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  • 10 years later...

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