News. STRANGE news.
#1
10-10-2009, 10:50 AM
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News. STRANGE news.
Both the new Toyota Venza and 2010 Lexus RX350 now use the same F/awd system, at least in basic concept, as the FE/FEH, MMH, Tribute, CX-7, etc. The newest Porsche 911 also but as R/awd.
Both the Venza and RX350 have a thermistor within the rear driveline clutch case along with dash warning lights to notify the driver that the electromagnetic clutch is beginning to overheat (slow icon flashing), HAS overheated (fast flashing), with the standard warning we saw in the FE back a few years ago.
Another interesting aspect is that only the RX350 has a manual 4WD LOCK capability wherein the rear driveline will be virtually locked into synchronization with the front drive until/unless the vehicle speed reaches 25MPH.
Even in this manually locked mode the rear driveline gets uncoupled upon brake application, VSC (stability control), or TC activation. The rear coupling coefficient is still reduced when turning.
So.
Mazda is water cooling the PTO to prevent driveline damage due to windup or tire scrubbing and Toyota/Lexus is using the "old" Ford method..."if what you're doing hurts then stop what you're doing."
Does that mean that the current FE/FEH F/awd system was detuned/derated so serverely that the previous technique, "stop what you're doing", is no longer required...??
Anyone have a different explanation...??
Oh, and the really "old" FE F/awd system also had a manual LOCK switch.
Both the Venza and RX350 have a thermistor within the rear driveline clutch case along with dash warning lights to notify the driver that the electromagnetic clutch is beginning to overheat (slow icon flashing), HAS overheated (fast flashing), with the standard warning we saw in the FE back a few years ago.
Another interesting aspect is that only the RX350 has a manual 4WD LOCK capability wherein the rear driveline will be virtually locked into synchronization with the front drive until/unless the vehicle speed reaches 25MPH.
Even in this manually locked mode the rear driveline gets uncoupled upon brake application, VSC (stability control), or TC activation. The rear coupling coefficient is still reduced when turning.
So.
Mazda is water cooling the PTO to prevent driveline damage due to windup or tire scrubbing and Toyota/Lexus is using the "old" Ford method..."if what you're doing hurts then stop what you're doing."
Does that mean that the current FE/FEH F/awd system was detuned/derated so serverely that the previous technique, "stop what you're doing", is no longer required...??
Anyone have a different explanation...??
Oh, and the really "old" FE F/awd system also had a manual LOCK switch.
Last edited by wwest; 10-10-2009 at 10:54 AM.
#2
10-10-2009, 03:29 PM
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Re: News. STRANGE news.
The following same info appears in the '05, '06 and '07 FE/FEH Workshop Manuals but doesn't appear in the '08-'10 manuals. The heat protection mode is mentioned along with the lock mode, cooling but nothing about the dash indicator.
Heat Protection Mode
During very extreme off-road operation, the 4WD system has a heat protection system to protect the active torque coupling from damage. If the system detects an overheat condition, it enters a locked mode and turns on the 4WD indicator light in the instrument cluster. If the heat in the system continues to rise once in the locked mode, the 4WD control module disables the active torque coupling and causes the 4WD indicator light to flash continuously.
4WD Indicator Light
4WD — Illuminates continuously when the 4WD system is locked in 4WD due to its heat protection mode. In the locked mode, the vehicle resists turning and binds up when driven on dry pavement. To exit the locked mode, stop the vehicle and allow it to cool for 5 minutes with the engine running. When the 4WD indicator turns OFF, normal 4WD system function is restored.
4WD — Blinks continuously when the 4WD system is disabled due to its heat protection mode. To exit the disabled mode, stop the vehicle and allow it to cool for 5 minutes with the engine running. When the indicator turns OFF, normal 4WD system function is restored.
4WD — Blinks 3, 6, 8 or 10 times every minute when the 4WD system requires service. Use a scan tool to check for diagnostic trouble codes (DTCs). Refer to the Four-Wheel Drive (4WD) Control Module Diagnostic Trouble Code (DTC) Index in this section
Heat Protection Mode
During very extreme off-road operation, the 4WD system has a heat protection system to protect the active torque coupling from damage. If the system detects an overheat condition, it enters a locked mode and turns on the 4WD indicator light in the instrument cluster. If the heat in the system continues to rise once in the locked mode, the 4WD control module disables the active torque coupling and causes the 4WD indicator light to flash continuously.
4WD Indicator Light
4WD — Illuminates continuously when the 4WD system is locked in 4WD due to its heat protection mode. In the locked mode, the vehicle resists turning and binds up when driven on dry pavement. To exit the locked mode, stop the vehicle and allow it to cool for 5 minutes with the engine running. When the 4WD indicator turns OFF, normal 4WD system function is restored.
4WD — Blinks continuously when the 4WD system is disabled due to its heat protection mode. To exit the disabled mode, stop the vehicle and allow it to cool for 5 minutes with the engine running. When the indicator turns OFF, normal 4WD system function is restored.
4WD — Blinks 3, 6, 8 or 10 times every minute when the 4WD system requires service. Use a scan tool to check for diagnostic trouble codes (DTCs). Refer to the Four-Wheel Drive (4WD) Control Module Diagnostic Trouble Code (DTC) Index in this section
#3
10-10-2009, 06:41 PM
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Re: News. STRANGE news.
The following same info appears in the '05, '06 and '07 FE/FEH Workshop Manuals but doesn't appear in the '08-'10 manuals. The heat protection mode is mentioned along with the lock mode, cooling but nothing about the dash indicator.
Heat Protection Mode
During very extreme off-road operation, the 4WD system has a heat protection system to protect the active torque coupling from damage. If the system detects an overheat condition, it enters a locked mode and turns on the 4WD indicator light in the instrument cluster.
Okay, known FACT, the ATC is overheating because too much stress is being put on the overall driveline, continuous driveline windup and/or tire scrubbing. And yes, locking it will (should) result in reducing the clutch slippage and thereby lower its heat load.
But what if the driveline stress, tire scrubbing continues, what is the next weakest link...?
If the heat in the system continues to rise once in the locked mode,
This statement I don't get, entirely don't get. Why would the design engineers have the expectation, experience, of continuing heat rise in the clutch and not realize that the design is flawed..??
The only reason I can see for a continuing rise in heat level once the clutch is LOCKED is that there is such a heavy load being put on teh driveline that the clutch continues to slip.
Were I the design engineering team leader knowing the above information I would ask my team for a redesign.
the 4WD control module disables the active torque coupling and causes the 4WD indicator light to flash continuously.
4WD Indicator Light
4WD — Illuminates continuously when the 4WD system is locked in 4WD due to its heat protection mode. In the locked mode, the vehicle resists turning and binds up when driven on dry pavement. To exit the locked mode, stop the vehicle and allow it to cool for 5 minutes with the engine running. When the 4WD indicator turns OFF, normal 4WD system function is restored.
4WD — Blinks continuously when the 4WD system is disabled due to its heat protection mode. To exit the disabled mode, stop the vehicle and allow it to cool for 5 minutes with the engine running. When the indicator turns OFF, normal 4WD system function is restored.
4WD — Blinks 3, 6, 8 or 10 times every minute when the 4WD system requires service. Use a scan tool to check for diagnostic trouble codes (DTCs). Refer to the Four-Wheel Drive (4WD) Control Module Diagnostic Trouble Code (DTC) Index in this section
Heat Protection Mode
During very extreme off-road operation, the 4WD system has a heat protection system to protect the active torque coupling from damage. If the system detects an overheat condition, it enters a locked mode and turns on the 4WD indicator light in the instrument cluster.
Okay, known FACT, the ATC is overheating because too much stress is being put on the overall driveline, continuous driveline windup and/or tire scrubbing. And yes, locking it will (should) result in reducing the clutch slippage and thereby lower its heat load.
But what if the driveline stress, tire scrubbing continues, what is the next weakest link...?
If the heat in the system continues to rise once in the locked mode,
This statement I don't get, entirely don't get. Why would the design engineers have the expectation, experience, of continuing heat rise in the clutch and not realize that the design is flawed..??
The only reason I can see for a continuing rise in heat level once the clutch is LOCKED is that there is such a heavy load being put on teh driveline that the clutch continues to slip.
Were I the design engineering team leader knowing the above information I would ask my team for a redesign.
the 4WD control module disables the active torque coupling and causes the 4WD indicator light to flash continuously.
4WD Indicator Light
4WD — Illuminates continuously when the 4WD system is locked in 4WD due to its heat protection mode. In the locked mode, the vehicle resists turning and binds up when driven on dry pavement. To exit the locked mode, stop the vehicle and allow it to cool for 5 minutes with the engine running. When the 4WD indicator turns OFF, normal 4WD system function is restored.
4WD — Blinks continuously when the 4WD system is disabled due to its heat protection mode. To exit the disabled mode, stop the vehicle and allow it to cool for 5 minutes with the engine running. When the indicator turns OFF, normal 4WD system function is restored.
4WD — Blinks 3, 6, 8 or 10 times every minute when the 4WD system requires service. Use a scan tool to check for diagnostic trouble codes (DTCs). Refer to the Four-Wheel Drive (4WD) Control Module Diagnostic Trouble Code (DTC) Index in this section
#5
10-11-2009, 08:40 PM
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Re: News. STRANGE news.
Are you just plain to CHICKEN to back up your words with a few FACTS...?? Why is there such a great propensity on these posts to say "you're wrong" without providing any information as to why.
#6
10-13-2009, 03:37 PM
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Re: News. STRANGE news.
Still wondering about my "ignore" list?
#8
10-19-2009, 09:43 AM
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Re: News. STRANGE news.
Trouble is, you have no facts.
Once you recommended that people put gear oil in their transaxle instead of the Ford recommended ATF, I began taking what you say with a salt shaker close by.
Once you recommended that people put gear oil in their transaxle instead of the Ford recommended ATF, I began taking what you say with a salt shaker close by.
#9
10-19-2009, 10:40 AM
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Re: News. STRANGE news.
If you think that to be the truth they why not post a link...??
