Rx330 Trans Oil

[first rx]

Does anyone out there work as a Toyota Tech? What is so special about Toyota trans oil? Why do people complain about trans problems after changing the oil? Can Mobil 1 ATF be used as a replacement oil? The specs on Mobil 1 ATF say meets or exceeds all manufacture specs. I have used it on everything I've owned since 1995. But....never on a a Lexus. Also, I understand that there is not a regular filter inside the trans, it is a screen. Would adding an external filter do a better job than just a screen?

I have been a truck fleet mechanic for 20 years, and have never heard of a trans that does not require fluid and filter changes to extend the life. The main enemy of trans oil is heat, and if you can keep the oil fresh, you extend the life.

Bob

[RX in NC]

Search this forum using "transmission failure" or "transmission problems" as your key words and you'll uncover a huge selection of posts that pertain to this topic on the RX series. In a nutshell, you need to understand that the transmission is the weakest component in the all-wheel-drive RX series, and you must undertake preventive measures to give yourself the best chance of extending the life of this transmission. Many of us owners believe that there are design flaws of various natures in these transmissions. You are correct in assuming that keeping fluid fresh and as cool as possible is probably the best insurance you can provide towards holding off an early breakdown. Our properly-maintained 2000 RX300 AWD transmission failed at about 48,000 miles. It was replaced under warranty and the vehicle has just passed 90,000 miles. It's my wife's primary vehicle, and I baby the care and feeding of this transmission like no other I've owned during my 35-plus years of driving. Here are my recommendations to you:

1. I doubt if there is any significant chemical advantage to Toyota Type T-IV transmission fluid compared to other premium fluids out there on the market. But I would never run anything else in our vehicle simply because if you do, you provide Lexus with a convenient excuse to refuse to assist you when your transmission fails because you weren't running the recommended fluid. So stay with Type T-IV fluid in order to protect yourself from a legal standpoint.

2. Regardless of what your owner's manual says, change your transmission fluid at least every 30,000 miles. Some owners on this site insist on doing so every 15,000 miles. The bottom line is that in order to have a chance for your original transmission to last as long as the vehicle is supposed to, you MUST keep clean fluid in it. If you don't, your transmission is gonna fail early. You can count on it.

3. A number of RX owners on this site have discussed installing an external transmission cooler, but I'm not sure if anyone has actually done so yet. The consensus seems to be that if you're gonna tow something, you'd better add an external cooler. I would never even consider using our RX to tow anything; I don't believe it is engineered strongly enough to do so, especially the transmission. These vehicles are overweight and underpowered - they are neither good tow workhorses nor off-roaders.

So spend some time searching this site for transmission-related issues on the RX series. You'll gather a great deal of helpful information and be better prepared to deal with your particular vehicle as a result.

One thing is for certain in our household - when we dispose of my wife's RX300 at 130,000 miles or so, it will not be replaced with another RX. Out of the 25 or so vehicles I've owned since 1969, it has been by far the most disappointing because it has required so many expensive repairs to major systems even though, like all of my vehicles, it has been meticulously maintained.

The newer-generation RX330s may prove to be better designed and constructed, but the jury is still out. But for many of us, the RX300 AWD transmissions have been problematic since early in the ownership experience.

[monarch]

What is so special about Toyota trans oil? Why do people complain about trans problems after changing the oil? Can Mobil 1 ATF be used as a replacement oil?  Also, I understand that there is not a regular filter inside the trans, it is a screen. Would adding an external filter do a better job than just a screen?

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Most Toyotas / Hondas / Nissans are about twice as reliable and durable as any American car and that's one reason why their resale value is so much higher. This greatly superior reliability & durability capability does not happen by magic, but happens only because the Asian car makers use superior grades of metal, plastic and rubber, superior component design and fit tolerances, superior standards of finish and workmanship for all the parts, superior fluids, filters and lubricants, etc. With regard to transmission fluid, Toyota / Honda / Nissan all have their own in house proprietary formulations such as Toyota Type T-IV. Using these in house formulations helps assure the owners will achieve maximum levels of reliability and durability.

With all that said, it appears the Toyota engineers did not engineer enough transmission fluid cooling capacity in the all wheel drive version of the RX300, particularly in congested city driving situations. So in congested city traffic in hot climates the fluid temperatures appear to soar into the 220 degrees+ range causing rapid oxidation of the fluid. The solution is frequent transmission fluid changes - approx. every 15,000 miles (10,000 miles for those owners stuck in bumper to bumper traffic on a daily basis)

Toyota has used metal mesh transmission filter screens for 40 years in all it's automatic transmission and they have always done a great job - one guy on this forum has 438,000 miles on a '81 Toyota Celica equipped with an automatic transmission that has a metal mesh screen. The screens rarely become restricted because they catch only non-magnetic wear debris. Toyota puts magnets at the bottom on the transmission oil pan to catch particles of steel from gears and other metal component wear.

No one on this or any other Toyota forum that I am aware of has reported longer transmission life after they installed an auxillary transmission oil filter. Frequent transmission oil changes is the best strategy, in my view, since it solves the fluid oxidation and fluid cleanliness issues at the same time. Auxillary fluid filters and coolers might or might not work, plus they might cause harmful restrictions in the fluid flow. And owners risk catastropic transmission failure if one of the aftermarket quality hoses used with the auxillary coolers developes a bad leak. Frequent fluid changes would seem to be the least risky choice of all.

[TunedRX300]

AWD has tranny cooler already, it is placed in front of the passenger front wheel and below the windshield fluid reservior. There are three ridge like holes on the plastic wheel well cover to let hot air escape - these holes do not exist on the driver side front wheel cover. Right hole from the front bumper serves as cool air inlet passage. But the circulation is terrible, not sure why Toyota choose not put cooler in front of the radiator.

Here is a discussion on tranny filter. I will do it as soon as my warranty expire.

Tranny Filter

[SKperformance]

Add the filter and you will save the headaches.

Do not use mobil 1 as it was also a start of my problems.

[TunedRX300]

There are about 16 qts of ATF in RX300 AWD's tranny, most is in torque converter. Drain & fill will replace only 4 qts, I would not mix Toyota T IV ATF w/ Mobil 1.

[first rx]

Thanks, sounds reasonable to me.

Bob

[monarch]

Thanks, sounds reasonable to me. Bob

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Everything boils down to a matter of risk. Owners who want to minimize the risk of premature transmission failure should:

1. Inspect the fluid condition every 5,000 miles and change it every 15,000 Change even more often if it appears to be getting dark and burned smelling inbetween changes. This strategy eliminates the inherent risk of extended fluid drain intervals.

2. Just drain and refill the 4 quarts in the transmission oil pan since this procedure is idiotproof, low cost, is the only procedure specified in the factory repair manual and has a 40 year / 400,000 mile Toyota transmission life track record. Flush flushing and other total fluid replacement procedures are aftermarket procedures and inherently more risky.

3. Use only the factory original fluid - Toyota Type T-IV. Using aftermarket fluids is inherently more risky. Although some synthetics claim to "meets or exceeds all manufacture specs." they have not been specifically tested and approved by Toyota as Toyota Type T-IV has been. Case in point: Mobil 1 systhetic gear oil "meets or exceeds all manufacture specs" yet nearly all Toyota owners who have tried it in their manual transmissions report increased gear clashing which means lots of metal gets chipped off the gear teeth.

4. Don't use auxillary transmission fluid filters*. The factory installed metal mesh filter screen has a 40 year, 400,000+ mile track record of providing excellent transmission protection. Auxillary filters sound fashionable just like synthetic fluid and fluid flushing sounds cool and fashionable, but some of the owners who push these filters as a means of preventing or curing transmisson problems are also some of the same ones who, at one time or another, admit using aftermarket fluids and fluid flushing. Had they followed steps 1 - 3, they wouldn't have ended up with abnormal amounts of wear debris in their fluid that caused their transmission problems to begin with.

*an auxillary filter may help temporarily salvage a transmission that has already suffered or is expected to suffer, traumatic levels of wear and tear due to use of aftermarket fluids, extended fluid change intervals and/or street racer type driving.

5. Follow the factory repair manual procedure for checking the fluid level as this is the only way

to guard against the serious consequences of under or overfilling.

6. As should be obvious by now, don't attempt to service the transmission without consulting the factory repair manual directions. Some transmissions, for example, have two drain plugs, not just one.