TunedRX300

My rear differential drain plug collect so much fine metal particles that Toyota's original GL5 oil around it has become black @ 54K. I would rather to get those metal debris out of the differential than leaving in, just my two cents...

ATF definitely needs to be changed every 30K and AWD has 0.8 liter more in drain and fill (3.9 vs 3.1), but rear differential is unique to AWD. See the drive shaft output of AWD tranny, FWD does not have it. GL5 gear oil lubes where the drive shaft connects to the rear axel. $10 for 1 liter of 75w90 Mobil 1 and a 10mm allen wrench if you DIY, done at dealer is > $100. :chairshot:

Rear differential gear oil change every 60K.

Another discussion on a TSB on Lexus brake pads making noise. TSB on Lexus Brake Pads Noise OEM Brake Pads Shifting Noise TSB

Go to your nearest Lexus dealer and have your tranny checked. I hope your powertrain warranty has not expired.

I wonder how your speedometer could be giving you an incorrect reading? Did you change anything about the tires? ← Tire thread is wearing down, making tire diameter shorter than new. Legal minimum is 2/32, new tire is 10/32, that is 1/2 inch difference in diameter or 1.57 inches difference per rotation. Your car has a predetermined distance per revolution that may not be accurate as tires are becoming bald. Odometer and speedometer both are affected when tire/rim diameter change.

Search "rear main seal" then go under your front axel and see if you have oil leak. Check your front side markers when you turn on parking light, if they don't light up, you have a burned/rusted out bulbs.

Yes, the car is more aero-dynamic. It will help in higher speeds to cut down drag.

I'd rather THEM do --- for FREE! ← Good luck, incadescent light bulbs do not last forever. Most people don't expect their desk lamp bulbs to last five years - that is in a non-moving environment.

I would replace it with a LED, DIY and save $ D light DIY

Here is a link to the bubbling problem reported by another member Corrosive Brake Dusts from OEM pads For 99-00 RX300, Toyota pad covers only 3/4 of friction surface on rear rotors. Most cars, including Toyota 4 Runner matches rear pad size with rotor friction surface width to maximize ability to stop. Over time, a rust ring with width close to 1.5 cm will form on friction surface. Really ugly to look at since 3/4 of rotor is shining and 1/4 is rust brown. This is poor design unless someone can come up with a good reason why rear pads are so tiny. A smart designer should at least match the pad size with the existing rotor size so full potential of braking system is utilized.

Marginal pads because I have bubblings formed under clear coat of my OEM rims. Two Lexus dealers told me dusts from OEM pads are to blame, of course, both of them denied repair under warranty since painting on rims are not covered under paint corrosion warranty. To be fair, I never has squeak issue with OEM pad. The corrosion is a common one for all semi-metallic pads. That is why I want to go to a different pad material - ceramic, which has less dust than OEM and similiar friction coeficient. Many owners report Lexus replacement front pads do not have integrated wear indicators - you need to reuse original clip-on wear indicator, forever. This is an unusual design since most shops throw away old shims with used-up pads. Guess what they do with the clip-on indicator? Most of the time tech will throw it away thinking they are old shims. This is a poor design because it is not service friendly. If you talk about wear on rotor by high friction coeficient pads, what about the high possibility of many RX w/o wear indicator and only find out after rotors are damaged by metal on metal contacts. See what mikey00 found out when he bought Irontoad's OEM pads RX300 w/o on pad wear indicator

Ceramic pads are quiet, www.rockauto.com, for the same $ to pay for OEM pads (marginal at best) I got Akebono Proact Ceramic $49 shipped with this discount code Rock Auto 5% Off Go to EF1 in Signal Hills if you don't want to install yourself. They are a approved TireRack installer and very professional. EF1 Brake Price $75 per axel, EF1 uses torque wrench (not impact wrench as in many shops including Lexus) to properly torque your wheel nuts and avoid brake rotor warping. Shop is clean and when I have my rotors and pads installed there for $75 , the tech was really careful not to scratch the rotor and wipe everything, including his fingerprints on newly installed rotors, clean afterward.

May be switched but as long as you have magnet on the drain plug, does not matter. My fill plug is on the side but it is couple of inches higher than the drain plug, i used a pump to fill about 1 qt of GL5.

Interesting, my RX AWD has blue 15/16 as the fill plug, it is facing the rear. The drain plug also is 15/16 and has a yellow label and facing down, just couple inches down from the fill plug. What is the size of your fill plug, does it have a crush filter when you loosen it?

That looks like my fill plug, it is blue but says 85w90, facing toward the rear and perpendicular to the ground. I think you mean drain plug is horizontal to the ground- not vertical. I used a craftsman 15/16 open end wrench to get the drain plug off. There is not enough space to latch completely. I patiently angle the wrench until I got a good hold. Careful not to strip it and soak the drain plug with WD40. I am not sure where your gear oil went, but it is not a good sign to pour one qt without draining. You need to loosen the drain plug to wipe off metal debris collected on the magnet.

Could you describe the fill plug (size, location)? When I loosen mine, gear oil started to drip out caused by the tilt when I jacked up the passenger side.

Brake dusts are corrosive, soon after this member posted about bubbling of paint on OEM rims, I found my rims' paint bubbling also. Brake Dust Corrosive Lexus dealer said dusts from OEM pads is to blame, in the next sentence, refused to repair under paint warranty since it is not included. To be fair, I spent two winters at NYC so perhaps road salt also contributed. But the member in the above thread is in SF, CA - no road salt there for sure.

Monarch, See what this SAE expert say about #2 and #3 reasons you posted in this USA Today report. Premium Not Necessary Better This link is posted by a member in the maintence thread, I select a few quotes from Nissan, Toyota, SAE and FTC experts in the article for those who are too lazy to click . ""I personally use regular even though my owner's manual says you'll get better performance with premium," says Lewis Gibbs, consulting engineer and 45-year veteran at Chevron oil company. He's chairman of Technical Committee 7 on Fuels, part of the Society of Automotive Engineers (SAE) Fuels & Lubricants Council. Gibbs knows gas." "Premium, in fact, sometimes is worse fuel than regular. It resists knock because it's harder to ignite than lower-octane fuels. As a result, some engines won't start as quickly or run as smoothly on premium, notes Gibbs, the SAE fuel expert. High-test does have a potential fuel economy benefit. It is slightly denser than lower-octane gas, meaning there's a little more energy in a gallon. But the small difference is hard to measure in real-world use, and that same density can contribute to undesirable buildup of waste products inside the engine. No data show that engines designed strictly for regular run better or longer on premium. The Federal Trade Commission, in a consumer notice, emphasizes: "(I)n most cases, using a higher-octane gasoline than your owner's manual recommends offers absolutely no benefit. It won't make your car perform better, go faster, get better mileage or run cleaner." There is "no way of taking advantage of premium in a regular-grade car," says Furey. "There is no gain. You're wasting money," insists Jim Blenkarn, in charge of powertrains at Nissan in the USA. "No customer should ever be deluded into thinking there's any value in buying a higher grade of octane than we specify," says Toyota's Paul Williamsen, technical expert and trainer."

Do have aftermarket semi-metallic pads? They are notorious for generating tons of brake dusts. Go for ceramic for low dust, I have Akebono, rockauto.com for $49 shipped using a 5% coupon that I found by Google.

Let's not play the guilt card here. There is already enough Lexus owners who were led to believe 91 Octane is the minimum by oil companies. "Premium car MUST need premium fuel" Octane rating of 87 is within Toyota's official recommended range - warranty is honored by Toyota. Now on topic: how does the octane rating of fuel affect tranny's ability to shift smoothly?

This is an excellent article that another member posted on the maintenance forum. August 27, 2003 “I only use super/premium/performance/ high octane fuel in my Civic DX. I can feel the power…” This is probably one of the biggest misconceptions in the automotive world, as we know it. Yet, I hear this all the time. For example a close friend of mine who drives a 1996 Pontiac Bonneville tells me that he only uses Chevron 92 octane fuel because “It performs so much better, and my fuel economy is way higher.” This opinion or misconception is not an isolated view to the “gear-heads” that are or think they are car savvy. And the oil companies don’t help the matter by calling their high-octane fuels “Performance” or “Premium,” or whatever they choose. Here is why. The first thing we have to know is obviously, what is octane and why does it matter? Octane can be simply defined in one sentence: Octane is a rating of a fuels resistance to ignite (evaporative qualities). WAIT A MINUTE! Resistance? That’s right, resistance. To put it simply, the higher the octane, the harder it is to get to ignite. Higher-octane fuel resists burning. Lower-octane fuel does not. Lower-octane fuel is actually more explosive, move volatile, and creates a much bigger explosion then its higher-octane counter-part. When you go to the pump to fill your car, you generally have three options. Regular, mid-grade, and super. You also see that there is a rating system. It is a sticker posted to the pump next to the octane rating of the fuel that you choose. It generally says something like this. Regular for example: 87 Octane minimum, measured by using the (R+M)/2 rating. What does this mean? The R in the equation stands for Research Octane Rating, known as RON. This is a test that tries to simulate variables that your car would go through on a given day. It is a test using a single cylinder, four-stroke engine that is idling at 600rpm. The fuel temperature going into the engine is not controlled. It is allowed to vary and fluctuate with the temperature of the conditions at the time. The intake air temperature is varied with barometric pressure to simulate the air being sucked into the car from the outside. The timing is set at 13° BTDC. This is done to covert everything to a SAE standard day, which is 60° F, 0% Humidity, and 29.92 inches barometric pressure. The M in the equation stands for Motor Octane Rating, known as MON. When testing MON, the fuel is heated to 300° F and the intake air is heated to 100° F. The test engine is a single cylinder 4-cycle engine that is run at 900 rpm. Ignition timing is varied with compression ratio. Engine load is varied during test. If you are deciding what fuel to use on a high-compression, high-performance engine, this is the test you would want to use. The RON will always be higher than the MON. So what does this all mean when you go to the pump? It means that to extract the most from the car that you are driving, you have to use the appropriate octane fuel or the car is not going to perform up to its potential. Either the fuel will burn too slowly, and in many cases not burn completely, or it will burn too fast and out of control. The latter is called Detonation. Normal combustion will take place at a pretty steady rate (for a given rpm and load), when a large amount of the charge burns extremely fast and uncontrollably, it is know as detonation. Detonation can destroy an engine in a matter of seconds. There are a few causes of detonation. Usually it is attributed to too much heat, but that is only part of the problem. Pressure and advanced ignition timing both play a role in it too. Usually when detonation takes place, the detonation occurs on the intake side of the chamber, which is the coolest side of the chamber. This happens because detonation did not occur until the pressure got excessive, which was after the spark. By the time that happened, the charge near the exhaust valve has already been burned. Most of the time, detonation will occur after normal combustion has started. Apart from destroying pistons and spark plugs, light detonation can cause all sorts of other problems, like fatiguing cranks and rods quickly and pounding bearings to death, so avoid detonation at all costs. Another problem is Pre-ignition (for cars using octane that is too low). When the charge lights off before the spark, it's called pre-ignition. This can happen with or without detonation, but usually will cause detonation in a high performance engine. Hot spots in the combustion chamber are the usual cause of pre-ignition. This is very unpredictable and can lead to detonation, because it will act just like too much ignition timing, but it won’t be controllable. So this is what happens in cars that use octane ratings that are too low, but what about vise-versa? Generally, the problem with using an octane rating that is too high for your car causes problems that, while not generally as severe as going too low, are still detrimental to the performance and efficiency of your engine. One of the most common problems is lost power. Yes, you read that right, if you use an octane of fuel that is too high for your car, you will lose power. This goes for all the stock or lightly modded Civics out there. Remember when we discussed that octane measures the fuels resistance to burn? Well, this is where that really comes into play in a low compression engine, such as the engines found in 90% of all streetcars. As the fuel is injected into the combustion chamber and the compression stroke begins, cylinder pressure is created. This is vital to combustion as cylinder pressure is what translates into power. When that pressure is not high enough (low-compression), the fuel only partially ignites. This means that there is leftover fuel that has to be expelled through the exhaust valves and expelled through the exhaust. This is bad for several reasons. The first is that this un-burnt fuel leaves deposits and grime all over the cylinder and valves. This robs you of power, fuel economy, and wears engine components pre-maturely. There is also a vital part of any streetcar, the emissions control devices. The catalyst for example often is destroyed by being clogged with carbon and un-burnt fuel resulting from using too high-octane. This results in costly repairs, and guess what? The loss of power and lower fuel economy. Not to mention, you had to pay $.20 more per gallon just to lower your cars potential and performance. So you guys that think that adding 100 octane race gas to your Civic Ex at the track is going to improve your times, you are running in the wrong direction unless you have some kind of forced induction such as Nitrous, Turbo, or Super Chargers. So the next question people ask is, “Why then do high-power, ultra-fast cars use high octane fuel?” Well the answer is simple. Higher-octane fuel contains more POTENTIAL energy but requires the higher heat generated by higher compression ratio engines to properly condition the fuel to RELEASE that higher potential energy. Here is the general rule for choosing octane if you have a question of what it should be. If your compression is 9.5:1 or lower, 87 octane should be plenty. As your compression rises, so should the octane that you choose. Remember that there are variables to everything in life and this is no exception. If you have dramatically advanced ignition timing for example, high-octane may be needed. But for the vast majority of the people on the street, for optimal performance in your streetcar, use the octane best suited for your car, and remember, high-octane does not mean more power! Coby Burns (Writer of above topic not forum poster) Found this at http://www.speedupgrade.com/articles/article/692608/5136.htm

Give the guy a break, many RX300 owners do not even know how to change air filter, which do not require any tool or lifting.

Would be interesting for you to find out the octane rating for 2004 Camry V6, it has the same 3MZFE. This is what posted on the thread in the maintence forum on what is in ES's user manual " SW03ES, it is very odd, the 02 and 03 are basically the same car with the addition of adjustable pedals in the 03. BUT: the 02 manual calls for premium and says a lesser grade could be used in a pinch. the 03 manual calls for regular grade and says to use premium for improved performance. My guess is too many people complained that they "had" to buy premium so the coorporate suits reworded the section to quiet the masses and keep their behinds covered. steviej"

There is already a 2 year long thread on octane gas in the maintenance section. Let's not go off topic and start another debate here. Octane Thread My question is the same as wwest, how does octane grade of gas, which burns in engine, helped tranny to shift gear smoothly? It is equivalent of saying whatever is used (coal, nuclear, solar) to generate electricity at power plant helps transformer to step up/down the voltage of electricity delivered to your house. It is absurb unless there is a convincing reason.