10-25-2011, 09:57 PM | #2 | |
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You must use "car wash" mode: Last edited by Lotus7; 10-25-2011 at 10:03 PM.. |
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10-25-2011, 10:06 PM | #3 |
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Good question. If your battery is dead or other electrical issue, how would you have the car towed, even brought onto a flat bed if the brakes are engaged?
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10-25-2011, 10:34 PM | #4 | |
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I once saw an illegally parked (RWD) Lexus in downtown Chicago being dragged away by a tow truck with it's front end raised and the rear wheels on the ground. The transmission was undoubtedly in Park. The tow truck started moving, the rear tires skidded for about 50 feet and then there was a very loud "bang". Then the rear wheels began to turn. The transmission park mechanicals were certainly broken, and the owner was going to be paying lot more than just the parking and towing fine. Ouch! |
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10-25-2011, 11:39 PM | #5 | |
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10-26-2011, 12:23 AM | #6 | |
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Dear Judd-Pollyanna-holland, Unfortunately, what might be expected of competent tow truck operators and what's provided are often not the same. The example I mentioned, which was dramatic enough that I can still remember small details, occurred on Jackson Blvd. just east of State. There were temporary, paper no-parking signs posted because they were going to do some overnight street patching, and the Lexus and several others were parked there anyway. The tow truck was a blue City of Chicago truck, and the driver's ONLY priority was to remove the cars as fast as possible. The driver spent all of three minutes hooking up and towing away the Lexus. Last edited by Lotus7; 10-26-2011 at 12:34 AM.. |
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10-26-2011, 02:18 AM | #7 | |
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What is transfer case clutch? If battery is dead ( or goes dead while car is parked?) the transmission P is in fact same as N? The transmission is not locked when in P if battery dies? Ie. if you park on a steep hill without parking brakes, your car will slide down if battery dies? Oops... Or is it so that front wheels can roll freely "in battery dead mode" even if gear is on Park. And that will not cause center differential to explode...? I remember that if a big truck must be towed, you have to detach driveshaft from rear end in order to keep transmission in good shape. A nice picture would do a lot of explaining... what all rolls free if gear is on P and battery dies? |
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10-26-2011, 05:04 AM | #8 | |
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Over here and in Moscow, where I spent my last couple of years, they use only flatbed trucks with cranes. They are more careful, but they still dent and scratch cars. |
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10-26-2011, 07:40 AM | #9 | |
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Park Mode: Although the transmission selector "Park" mode "brakes" the rear wheels, it is not actually a brake. Pressing the "Park" button on the gearshift lever OR shutting off all vehicle power engages a mechanical park "pawl". The "pawl" is a metal pin that drops into a gearwheel connected to the transmission output shaft (which is always connected to the rear driveshaft) that prevents it from turning. The park "pawl" will engage automatically when no power is applied. Ignition COMPLETELY off (second button press) OR dead battery= transmission locked = rear wheels locked. It's just like a older car with a mechanical park position on the gearshift, it will stay in park. When parked on a hill, the E-Brake should be used to hold the vehicle (and the front wheels turned to the curb), not just the transmission "Park' mode which will stress the transmission if used alone. E-Brake: The Electronic "Emergency Brake", operated by the "pull/push" switch on the console behind the gearshift lever (often called the "Parking Brake") actually is a real braking system. When the E-Brake switch is actuated, a powerful electric motor operates mechanically to pull two metal cables that are coupled to the rear wheel brake calipers. The brake pads are engaged mechanically through the calipers. You can feel the brake pedal drop as the cables reduce hydraulic pressure in the rear calipers by mechanically pressing the pads. The motor is used to engage the E-Brake cables and is used again to dis-engage them. If the Brake Hold is on (green light), the E-Brake (red light) will automatically engage when the car ignition is shut off. The rear-only E-brake will remain in whichever state it was in when the power was removed. A dead battery will not apply the E-Brake if it was previously off, but without battery power, the E-Brake will not operate either. E-Brake only can lock the rear wheels. Because of the transfer case clutch, the center differential will not explode if the vehicle is moved a short distance (enough to get it onto a flat bed truck) with the rear wheels elevated at low speed. It's effectively disconnecting the front drive-shaft, but not the rear drive-shaft. Even if the vehicle is in "Park" the front wheels are free to rotate (but NOT the rears). However, if the rear wheels rotate when in "park" (transmission park mode - not E-Brake "Park") the transmission will be likely be damaged. In Neutral the park pawl is disengaged and the vehicle can roll with no damage, but ONLY if the ignition is on, ONLY if the E-Brake is off, and ONLY if there is battery power. Sorry it's so complicated, but BMW designed it, not me. Last edited by Lotus7; 10-26-2011 at 07:47 AM.. |
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10-26-2011, 10:36 AM | #10 |
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Thanks Lotus. It is not complicated and you described it well, at least in my point of view.
One thing only: if towed longer time "rear up" and front wheels rotating free on the ground (sort of one axle trailer style), can it do harm to center differential even though the TCC is disengaged? Maybe oil heating issues or something like that? And boy, am I now glad I ordered with manual stick! Hard to imagine that automatic electrocomic transmission working well for five years in here |
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10-26-2011, 11:25 PM | #11 | |
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Weeks before I was supposed to give up my 535 wagon end-lease back in December, I was involved in an accident. A woman stopped in the left lane on Lake Shore Dr. around the blind curve near North Ave. to CLEAN HER WINDOWS (because somehow the electric-ness of her Land Rover's windows never occurred to her). Long story short, one guy hit her, the next guy hit that guy, and I had no time to react after coming around the bend, so I collided with cars two and three, skidding between them and the barrier. I thought the car was effectively totaled. The front axle had snapped, the steering rack was finished, and there was significant body damage. The police, in their ignorance to the $70,000 station wagon with Four Wheel Drive that had just incurred damage equal to half its residual value, called not a flatbed to take it off Lake Shore Dr., but a typical, two-wheel fastener crane tow truck. I stared at it as the tow truck took it away down the exit ramp, listening to the rear wheels skidding across the pavement, and then I heard an echoey "clunk," followed by a nails-on-chalkboard whine. My beloved wagon was finished. And maybe, had more attention been paid to the kind of drivetrain on the car, it might not have been totaled, and Ms. Window Washer wouldn't have incurred over $40,000 in damages. She lost her insurance anyways. All's well that ends well, I guess. |
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10-26-2011, 11:44 PM | #12 | |
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I guess the German engineers suspect that American's won't know what to do with the third pedal. Our X3 is the first automatic we've had in the family in decades. So far, it's a fine transmission. (fingers crossed) Don't know if your use of "electrocomic" was a typo or a "Freudian slip". Either way it's very funny! There is a small amount of fluid in the TCC, and with only some of the parts turning it might not lubricate everything properly, so one would definitely NOT want to want to tow the X3 any distance or at even moderate speeds that way. |
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10-27-2011, 02:25 AM | #13 | |
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I used electrocomic on purpose. But I didn't know it has some actual meanings as well. We use that in Finnish sometimes when we mean electric device that we want to make fun of. |
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10-27-2011, 07:57 AM | #14 |
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Love it! Going to add it to my vocabulary and spell checker since the whole world is becoming "electrocomic". Thanks.
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10-27-2011, 12:55 PM | #15 | |
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He also stated they will all be that way soon. The current x5's still have the lever under the cup holder but that will change as well. Hope this helps. Last edited by s1948; 10-27-2011 at 12:57 PM.. Reason: wrong word |
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10-27-2011, 01:17 PM | #16 | |
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Of course, then there are those stories of cars parked in front of a hydrant and the fire trucks literally shoving them out of the way... and I'm okay with that.
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10-27-2011, 08:53 PM | #18 |
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This happened to somebody on the "other" forum. Makes for an interesting read:
http://www.bimmerfest.com/forums/sho...606&highlight= |
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10-27-2011, 10:32 PM | #19 | |
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