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The e-brochure for the 2005 AWD RX330 at Lexus.com indicates that the VC, viscous coupling, is back for 05. True?

Well, yes, and NO. To meet EPA ratings the gas tank is being kept in a slight vacuum so that vapors are trapped. The system detects when the cap is opened for refilling becuase the fill level will be higher when the cap is replaced. If you simply remove the cap without refilling then the diagnostic light will illuminate. same thing happens if the cap doesn't fully seal.

I case I haven't brought this up before. If you were driving a manual transmission vehicle you would always release the clutch shortly before coming to a full stop. That's exactly how my 01 RX feels except it also feels as if the clutch is released at higher speeds during a long coast. Having the engine/transmission in neutral or even in a low(er) torque drive gear when stopped or during coasting would undoutedly improve MPG and EPA ratings. Once the vehicle is EPA certified in this way I doubt if the EPA would look very kindly on a "fix" that reversed the emissions advantage.

Been thinking..............AGAIN! My 01 AWD RX300's transmission fluid has a burned look and odor at just 38k miles. This on a vehicle that has no tow hitch but with the tow package (extra transmission fluid cooler in front of right front wheelwell) and no designated fluid/replenish maintainance schedule. I have sent at least three missives to customer_satisfaction_inquiries@lexus.com and what I get back each time is that I should check with the dealer about why my RX has burned fluid. Apparently something they do not wish to put in writing. Up until just this week I have been assuming that the designers underestimated the heating contributed by the VC. But then I keep hearing/reading about these hesitation problems and that got me to thinking on another thread. I am absolutely sure that my 01's transmission shifts into another gear, or maybe even neutral, during coastdown. Some have described it as a "slingshot" effect or as if being bumped from behind just before coming to a full stop. I have attributed this effect to a desire to increase fuel economy and/or reduce the instances of loss of control on a slippery surface as the result of engine braking to the front, drive, wheels. But suppose for a moment that I'm correct and the vehicle is being shifted into neutral in these instances. My 01 DOES NOT have an e-throttle so the instant I depress the footfeed the engine will react and apply high output......while the transmission is still in neutral or an inappropreately higher gear?? Now THAT would result in premature BURNING of the transmission fluid! But now with e-throttle the later models might have a firmware fix that delays the onset of engine torque until the transmission can be shifted into the correct gear and allow time for the clutches or bands to be full seated before excessive torque is applied. Obviously just guessing, but....

Been thinking..............AGAIN! My 01 AWD RX300's transmission fluid has a burned look and odor at just 38k miles. This on a vehicle that has no tow hitch but with the tow package (extra transmission fluid cooler in front of right front wheelwell) and no designated fluid/replenish maintainance schedule. I have sent at least three missives to customer_satisfaction_inquiries@lexus.com and what I get back each time is that I should check with the dealer about why my RX has burned fluid. Apparently something they do not wish to put in writing. Up until just this week I have been assuming that the designers underestimated the heating contributed by the VC. But then I keep hearing/reading about these hesitation problems and that got me to thinking on another thread. I am absolutely sure that my 01's transmission shifts into another gear, or maybe even neutral, during coastdown. Some have described it as a "slingshot" effect or as if being bumped from behind just before coming to a full stop. I have attributed this effect to a desire to increase fuel economy and/or reduce the instances of loss of control on a slippery surface as the result of engine braking to the front, drive, wheels. But suppose for a moment that I'm correct and the vehicle is being shifted into neutral in these instances. My 01 DOES NOT have an e-throttle so the instant I depress the footfeed the engine will react and apply high output......while the transmission is still in neutral or an inappropreately higher gear?? Now THAT would result in premature BURNING of the transmission fluid! But now with e-throttle the later models might have a firmware fix that delays the onset of engine torque until the transmission can be shifted into the correct gear and allow time for the clutches or bands to be full seated before excessive torque is applied. Obviously just guessing, but....

There's snow, and then there is SNOW! Anyone who has skiied in various areas throughout the US will understand immediately. Driving on the cold, dry, powdery stuff is much like driving on 3 inches of loose sand. Almost any RWD, or even a FWD vehicle, even with summer tires will do fine. Out here in the nearby environs of Seattle we have what we refer to as Pacific Boilerplate. Anyone idiot enough to put only front chains on in this stuff would soon find themselves being dug out of the nearest barrow pit. Think for a minute about why in our mountainous regions truck-trailer rigs must use drag chains during the winter. And then think about what happens when you need to slow or stop quickly with front chains ONLY, especially driving down a slippery incline. Bye now....

lowered my 92 right after I got it. Look at the height sensor levers for the best "how-to" guidance.

The RX series most definately has a center differrential, an OPEN center differential! Prior to 04 there was a VC, viscous clutch, coupling, mounted across the two output shafts of the center diff'l which was dropped in 04 in favor of brake modulation for engine torque allocation and/or apportionment. On a 4 wheel dyno my 01 AWD RX had less than 5% of the engine torque applied to the wheels unless disparate roadbed traction was simulated by the dyno in which case the highest torque measurement obtained to the rear was 25% That, or course, was with a VC in place. The new model has virtually no torque to the rear unless front wheelspin is detected and therefore the front brakes are moderately applied to prevent wheelspin and "force" torque to the rear. In the above circumstance if the driver doesn't quickly lift the throttle to alleviate the cirumstance the engine will be quickly dethrottle to prevent brake rotor overheating. In other words once the system "switches" to AWD mode (moderate front brake application) no significant level of HP/torque can be applied anywhere, front or rear.

Looked everything over quite thoroughly last evening. Leak, seep, more descriptive, seems not to be mainshaft bearing seal, but out the end of what appears to be pressure relief spring area. Anyway not enough to worry about at this time. When I get home to Seattle I'll get one from a wrecking yard and overhaul and send it to my brother.

This past week I have been here in Memphis driving my brother's 92 LS. Power stearing fluid was low and Lexus parts guy was kind enough to personally top it off while reminding me that the alternator might fail if the PS leak continued. Lexus of Memphis quoted me $850.00 to replace power stearing pump. My shop manuals are at home in Seattle so has anyone done a repair for this and what parts do I need to buy before I begin?

Pardon, but the FX and the caddy are both rear biased AWD systems. The handling dynamics of FWD or RWD are so radically different in adverse roadbed conditions that I firmly belive the dealers should offer driving classes to folks who are switching from one to the other. And of course the same goes for front vs rear torque biased AWD.

Lexus uses a lower final drive ratio at the front that the rear so effective the front wheels will always have higher torque on the application of more power. The BMW X3, 5 AWD system, definite rear biasing, is one of the very best designs in the marketplace today. Lots of engine lagging torque for quick decleration when you lift the throttle. Drive one, you 'll love it.

Exhaust/gasoline smell under acceleration, especially uphill, is the result of having the cabin airflow exhauster port under the driver's side rear quarter panel. High air pressure under the car will force reverse flow.

Sorry, no fun.... At the first instance of wheelspin the brakes will "rattle", if you persist in trying to accelerate anyway the engine will be quickly dethrottled. Your 4runner can be accelerated and "thrown" into a turn but not the Rx.

Personally I wouldn't be at all surprised, given the hazards and potential liability of marketing an SUV with FWD or front biased AWD, to see the RX drive train redesigned to be rear drive based.

The RX330 AWD is really a FWD vehicle with the ability to route engine torque to the rear if front wheelspin is detected. Lexus uses a different, lower, final drive ratio at the front vs the rear so that the engine torque is heavily biased to the front, 95/5, in normal driving circumstances. If front wheelspin is detected then the front brakes are applied somewhat moderately to simulate roadbed traction and thereby force engine torque to the rear wheels. If the front wheelspin persists for more than a few hundred milliseconds then the engine will be quickly dethrottled to prevent brake rotor overheating and the resulting warpage. If you're really stuck, say in mud, after about 45 seconds of wheelspin activity the AWD system will shut down completely long enough for the fractional HP ABS pumpmotor to cool down so it doesn't overheat and fail. But a note of caution is warranted here. At our age it is entirely possible that we have spent most of our lives driving RWD vehicles, or in your case maybe even driving FWD vehicles but never in wintertime conditions. FWD, or front torque biased AWD can become EXTREMELY HAZARDOUS in wintertime conditions for an unsuspecting or inexperienced driver. Remember that with RWD if too much engine torque is applied, leading or lagging (engine braking) you still have roadbed traction at the front that you can rely on for recovery efforts. For FWD (or,) once the front wheels lose traction you are totally OUT OF CONTROL! As a safety measure Cadillac has now moved entirely back to RWD (they couldn't afford to lose any more of their loyal customers). But the previous FWD vehicles with the high torque/HP northstar engine was equipped with an over-running clutch in the tranny so no engine braking was available, and the engine ecu was programmed to INSTANTLY dethrottle the engine upon detection of wheelspin. Cadillac says that the engine was dethrottled if "impending" wheelspin was detected but I can not see how one would detect impending wheelspin. If you browse the various forums you will find many current complaints relating to almost all of the Toyota and Lexus FWD vehicles regarding complaints of hesitation and/or lack of quick acceleration. My personal opinion is that with the advent of e-throttles the manufacturers are taking action to help prevent loss of control accidents in the above described circumstances. The most common complaint seemed to be hesitation or lack of quick acceleration response when entering a turn and trying to accelerate simultaneously. This is exactly the prevenative measure I would expect if the manufacturers were trying to prevent loss of control of FWD vehicles where the driven wheels and the directional control, stearing wheels, or one and the same. Drive the AWD, definite rear bias, BMW X3 or X5 for an example of a really stable AWD platform under ALL circumstances. Oh, one further note, you cannot safely use snowchains with the RX300/330 or HL as shipped, suspension clearance above the rear tire is not sufficient. Toyota and Lexus both recommend snowchains be used ONLY on the front of there vehicles while simultaneously stating, within the very same owners manual, that an inordinate level of roadbed traction at the front vs the rear can potentially lead to loss of control. Their example is winter tires on the front with normal on the rear so you can see that snowchains on the front and not the rear would mean an extraordinary disparity between front and rear traction. I put 1.5" wheel spacers with 17x8 wheels all around on my 2001 AWD RX300 so that I could use rear chains as a first measure and then all four if and when necessary. Be careful out there.

Mould, mildew, and sudden spontaneous windshield fogging over. These problems have been with us since A/C began to be used, but became dramatically more prevalent with the advent of the use of the new, less efficient, refrigerant. When the LS400 was first introduced in 89 the A/C design was already r-134 compatible. Basically that meant a much greater complexity, density, for the A/C cooling evaporator, 10,000 square inches in the LS versus 4400 in an 84 T-bird. Another means to improve efficency was to dramatically reduce the cabin atmospheric outflow. The idea being that once the cabin atmosphere is cooled don't let it escape very rapidly. This last bit obviously had a positive effect on the fuel economy as now the A/C need not cycle on as often. The other result from more thoroughly sealing the cabin from outflow is that the system blower can be run at a much lower speed (less fresh air inlet) thereby improving the efficiency of the system to even a greater extend. The longer it takes the air to more through the 33F evaporator the colder it will become. So here we are in 1990, 91 with a SUPER efficient A/C system in preparation for the use of r-134 but the factory is still filling it with freon. Soon customer complaints start to come in about horrid A/C smells and sudden windshield fogging. So lexus decides that the odor problem can be overcome by coating the evaporator surface area with a porous nylon film into which is embedded an anti-microbial chemical to prevent the inordinant grown rate of the microbes that comprise the "family". Then things start to really go WRONG! First, they over-looked the Fed's requirement to file a form (MSDS??) acknowledging the use (and testing"") of a chemical fungicide to which ALL passengers in their vehicles will be exposed. And second, they completely overlooked the fact that with repeated "washings", daily use and non-use of the A/C, the result of which the chemical was quickly "leached" from those pores. That, of course, resulted in the porous surface now acting very much like a huge sponge, absorbing the moisture condensed on the evaporator and retaining it for much longer periods than would be normal. About a pound of water over a week of exposure sitting by itself, open, alone, in a closed two bay garage. And because that porous nylon film was created by human designed manufacturing process the pores themselves turned out to be of a fairly consistent size and/or volume. Those of you who are schooled in atmospleric sciences and have an understanding of "vapor pressure" are probably well ahead of me at this point. The suddenness of the complete and spontaneous fogging over of the interior surface of the windshield that many owners started experiencing with the arrival in the marketplace or the 92 model was directly related to the initial use of the nylon film containing the fungicide. I probably have the only existing copy of any Lexus documentation indicating the illicit use of the fungicide for that short period during late 91. So, the horrid odor of the out-gassing of the microbial spores breeding every night in 60-70F dark, dank and DAMP atmosphere of the AQ/C evaporator has been with us since the advent o fthe use of A/C. But the neeed to improve the efficiency of the system for the use of a new much less efficient refrigerant has obviously led to the horrid dirty gym socks odor being more pronounced and prevalent.

If you have traction control... There is a single electrically operated valve in the trunk that releases and applies brake pressure to prevent wheelspin. If that valve is stuck in the open position.......

The dash air outlets on the far left and right of the A/C system are NEVER closed, always open to system airflow, unless you close them manually. I have found that if they are almost closed but not quite then they are noisy.

The problem is really within the plenum containing the A/C evaporator, the heat exchanging device that cools and dehumidifies the airflow coming into the cabin. The odor results from the thin film of moisture that will always remain on the 10,000 square inches of cooling vanes surface area immediately upon shutting down the A/C. Absent some source of fresh airflow, forced or convection, this mositure may evaporate but most of it will remain within the plenum area. Dark, damp, dank, and about 65 to 75F overnight provides an excellent breeding area for the microbes that comprise the mould and mildew "family". The very best thing to do is leave the windows down every night, religiously, in the garage to allow the system to air out naturally. For more info go to airsept.com and read about their EED. I have heard that some dealers will exhaust a spray can of lysol into the air intake air just under the rear of the hood at the bottom of the windshield while the system blower is running on low or medium and in fresh mode. I wouldn't advise using the car for many hours afterward. Additionally I understand the above only provides a temporary fix, say a month or so, and the real answer is to keep the A/C evaporator dried out when not in use.

The smell is most likely the result of mould and mildew microbes BREEDING inside the damp and dark A/C plenum area. In order to prevent this I leave the windows down in the garage each night so the system will dry out form the previous day's A/C operation. This procedure will also help to alleviate the instances of windshield fogging over on the inside on cool or cold mornings. Go to airsept.com and see the writeup on their eed, electronic evaporator drier.

I think you mean defog or demist, defrost is usually an indication of ice on the outside of the windshield and lots of HEAT, MAX HEAT and high blower speed, is the only way I know to quickly solve that. Defog/demist: The A/C can ONLY dehumidify the incoming airflow if the Relative humidity is high enough that the A/C can cool it to its dewpoint. In the wintertime the air is nationally drier, lower overall relative humidity. So below about or below 45F the incoming atmosphere must have an unusually high moisture content in order for the A/C to substantially dehumidify it. Additionally, as the blower speed is raised above minimum the efficiency of the A/C for dehumidification will be decreased accordingly. So, if you have condensation on the interior of the windshield the very best thing to do is turn up the heat and the blower speed and leave the A/C OFF! And by the way, the A/C compressor is disabled automatically, and cannot be restarted although the indicator will come on, if the OAT declines to or below about 35F. If you should use the A/C for defog/demist on a cool day be aware that when it turn it off the A/C evaporator will be CLOGGED, virtually saturated, with the moisture just condensed from the airflow. With the A/C now off that mositure will be released into the cabin to radically increase the RH even about what it was before you used the A/C. Keep that windshield warm and avoid all of these problems. In the wintertime be careful to keep the system airflow to the footwell so that some of the airflow is toward the windshield to keep it warmed. In automatic mode ALL Lexus will switch to cooling mode(***) once the cabin's atmosphere approaches, rises to, the temperature setpoint. As of 01 the RX300 could be optioned via C-best to not automatically activate the A/C in normal mode and separately not in defrost/defog/demist mode. My 01 RX300 is set that way. Apparently the 04 RX has a c-best option wherein the system can be prevented from automatically going out of HEAT (footwell) mode when the cabin temperature setpoint is reached. Maybe other new Lexus' have the same feature. *** airflow from dash outlets or combined dash and footwell wherein NO airflow is directly routed to keep the windshield warmed and thus above dewpoint.

All Lexus, at least up until 01, default with A/C compressor on each time you start the vehicle. After 01 C-best option allows the dealer to change it.

The airflow reheat "blend" door/vane inside the plenum has a cable that operates the hot water control valve in the engine compartment. Located in the center at the top of the firewall. It should cycle from full closed to full open as you move from max cool to max heat. In the summer I often remove the cable from the valve and simply tie it closed so no hot water at all flows to the A/C system.

Clean and burnish the battery terminals/connectors