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Sedans Toyota Camry Toyota Camry Transmission Questions (MY Prior to 2007)
155 messages, Last post on Aug 20, 2009 at 5:25 PM
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| Hi. I posted on es300/330 forum, but I wanted to try this one too, since Lexus is made by Toyota (Camry). I am still having issues with tranny/engine mounts. Replaced the front (torque) strut but advised to change the other three mounts too. What may or will happen if the mounts are not replaced? I am assuming that these are original mounts - have 150K miles on the car. Others have said that they have more miles and have no issues. | |
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Replying to: sean300 (Aug 20, 2007 12:53 am) Thanks for advice. I noticed something else, which is the shifting happens in 3000 RPM, normally it was less than 2000RPM. Do these problems relate? (probably yes) What is your opinion? Regards
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Replying to: bkamali (Sep 01, 2007 6:59 pm) |
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[quote name='kolkh' post='127828' date='Sunday, Sep 2, 2007  06:24 PM']DISCLAIMER: Previous post is not a simple reply – this is actually 11-th edition of “Wwest Mythology”. Previous 10 editions have been discussed and bitten to death in approximately ~1000 posts in a number of forums/sites. I have read some of those. What is the result? See here: [url=http://www.siennaclub.org/forum/index.php?showtopic=6921&hl=]http://www.sie- nnaclub.org/forum/index.php?...ic=6921&hl=[/url] As if previous discussions do not exist, wwest posts the same stuff again and again and again… Like a Big Propaganda Machine, wwest is in a win-win situation: if you start infinite discussions and win – it does not mater, next time he will post exactly the same stuff. If you ignore him – he will flood forums and poor readers would have to deal with it anyway. END OF DISCLAIMER[/quote] Okay, "teacher" will take a different tact, tactic. Do you know how many things in a car simply waste energy....??? A) Power stearing hydraulic pump when there is no "stearing" to be done. What, 98% of the time? And yes, I do know that PS pressure helps "hold" the stearing in a "set" position, but just how much energy does that require in comparison to the HUGE losses? The PS must have the pumping capacity/volume/displacement to help, SERIOUSLY help, turn the wheels at or near a dead stop(parallel parking...), all the while with the engine turning only at idle, of maybe slightly above. So, 2200 RPM and driving straight down the highway at 65MPH guess how much pressurized PS fluid is simply being bypassed back into the sump. Is it any wonder that many cars are converting to electric power stearing, even at the risk of having the solid state electronics overheat and therefore automatically going into a sub-standard power assist mode? B] Gear-type engine lubricating pump. Again, pumping volume/capacity/displacement must accomodate full pressure and flow even with the engine at idle. So as engine RPM rises the EXTRA pumping capacity must be bypassed back into the sump. Either BMW or MB, don't remember which, has already gone to a variable displacement engine lubricating oil pump in oder to reduce these losses and thereby reduce the engine heat load and also increase FE. C) A/C compressor. Here again, the compressor pumping capacity must be such that it can provide FULL cooling capability at engine idle on a BRIGHT and SUNNY 100F (or above) day. In this case the A/C clutch along with a reasonably sized liquid refrigerant storage reservoir has been used for "eons" to ammiliate the effects of continuous engine loading by the A/C compressor. So why do you suppose so many new vehicles are coming out equipped with the new variable capacity "swash plate" type A/C compressor, and the compressor clutch? Because it is better design practice, overall, to have a continous ~2HP load on the engine rather than an intermittent load of ~7HP. [b]Getting the picture..?[/b] D) And just what is the deal with the torque converter (hydraulic TURBINE pump, slush pump, etc.), just how lossy is that sucker? The slush pump, torque converter, is really required ONLY to act as an automatic clutch. At low engine speeds, idle, the losses are so high that virtually no torque is coupled to the transaxle input shaft. NONE would be ideal, but nowadays you need a clutch pedal for that. The nice thing about the torque converter is that it also acts as a reduction gear ratio at low torque loading. But, that's where the torque converter lockup clutch comes into play. In OD it is highly desirous to have the engine operate at the lowest speed at which it can produce "just" enough torque for the current load factor...roadspeed. So at low engine RPMs the HIGH LOSS torque converter is bypassed by the lockup clutch. E) This one is slightly off point but I bring it because if I don't someone else will. The engine coolant water pump. Almost all engine coolant water pumps are of the centrifical, turbine, type and thereby self limiting insofar as pumping volume is concerned. Obviously there is some "needless" loss involved here otherwise the water hoses would not "swell", balloon, as engine speed rises beyond the point wherein the thermostat will accomodate the pump volume. Other than the current crop of hybrids, all equipped, to my knowledge, with electric water pumps, other manufacturers have already converted to electric pumps, if not altogether then at least apartially so, for the cabin heater. [b]Get the picture..? No...?[/b] F) And finally.... The gear type ATF pump. Like everything else above the most critical situation insofar as determining base pump volume occurs with the engine at idle. Hmmmm.. Let's think this over a bit. Just what "work" does the ATF pump have to do with the engine at idle? Shifting from park or neutral to drive or reverse is clearly not critical insofar as pumping volume is concerned... Upshifting once underway always involves engine RPM well above idle.... Aha, DOWNSHIFTING.... So, when does an automatic downshift with the engine at idle or nearly at idle. Not for passing, kickdown, certainly... But then how about just before coming to a full stop...? Or during coastdown periods with the throttle fully closed...? In both of these latter instances if the transaxle is to downshift lots of ATF pressure/flow will be required to ascertain the downshift clutches are quickly and firmly seated. Otherwise, with low or marginal ATF pressure these clutches would undoubtedly incur some serious level of slippage and the wear associated thereto. So, the engineers say to each other, if we could eliminate just these two instances the ATF pump FIXED capacity could be a LOT lower and that would undoubtedly inprove FE overall while reducing the heat load and clutch wear rate. Say, what does a stick shift driver do in these instances. Well as the cars coasts to a stop teh driver would normally disenage the clutch and slip the transmission into 1st. Well, we can't disenage the clutch....Can we...?? Sure can, simply "upshift" the transaxle a few notches, no substantial level of engine compression braking, NO transaxle clutch wear. Who cares if the upshifted clutches don't quickly fully and firmly engage...! But what about coastdown periods at 40-30MPH with the engine at idle...? Why not upshift then too, who's to notice? ________________________________________ The theory behind the above dissertation arose because I noticed a seeming abiguity between my earlier theory, "protect the drive train using DBW to prevent engine compression braking.' Owners have been reporting that while in cruise control the engine/transaxle ECU will actually command a downshift to retard roadspeed going down a hill. Me..."What? Downshift a FWD or F/AWD vehicle and actually take advantage of engine compression |
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Replying to: wwest (Sep 03, 2007 5:19 pm) That's not true for either of my Camrys ('04 with 4-speed auto and '05 with 5-speed auto). If descending a grade at highway speeds with the cruise control on, the car will remain in top gear. If the grade is steep enough, the car's road speed will increase above the set speed. ONLY by braking rather firmly will the transmission then downshift into 3rd (for the 4-speed unit) and 4th or 3rd (for the 5-speed unit). Of course, braking cancels the cruise control until the "resume" feature is activated.
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Replying to: 210delray (Sep 03, 2007 6:48 pm) ... the car will remain in top gear. If the grade is steep enough, the car's road speed will increase above the set speed. Is it the 2007 DBW model that downshifts? Your models act the way I want a car to do, even when cruise control is "off." I will move the lever to a lower gear if I want the car to downshift, and lose fuel economy in the process.
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Replying to: imidazol97 (Sep 04, 2007 4:26 am) |
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Replying to: 210delray (Sep 03, 2007 6:48 pm) So my cruise control downshift statement may, or may not, have been taken from a Toyota or Lexus post. |
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Replying to: sean300 (Aug 20, 2007 12:53 am) However today I used my A/C (I haven't used it during these days) and I noticed that the problem came back. Any suggestions? Thanks.
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Replying to: bkamali (Sep 20, 2007 4:28 pm) |
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