Mods: Can we get a poll to see if Willard's input is wanted here? That's the best way I know to see if he's actually representing the silent MAJORITY or the no-so-silent MINORITY.

 

Post a poll.

 

I'll vote for that!!

 

FYI...

The new 2010 RX350 F/awd system, like the Ford Escape, uses direct drive from the transaxle output to the rear driveshaft. At the end of the rear driveshaft a "linear" electric clutch is used to modulate, modify, the level of engine torque, 0-50%, delivered to the rear diff'l.

The functionality of Braking, ABS, VSC, EBD, etc, depends on the rear driveline being INSTANTLY decoupled upon activation of any of these "features", and that is the Lexus procedure.

The way I read the information the only time(s) the rear drive line will be automatically "coupled" is under HARD acceleration or with front wheelspin/slip arising from too much engine torque being used for road surface conditions. There is an intimation that OAT, COLD OAT will play a part in the level of torque automatically delivered to the rear drive line.

If the clutch is fully locked, as it can be up to 18MPH under driver pushbutton control, the driveline and tires will be forced to "absorb" any stress due to high roadbed traction. If the clutch is only partially closed/engaged then the clutch itself will be forced to absorb any undue driveline stresses, stressing.

The Ford manual WARNS that in this circumstance, linear clutch overheating, the system may go to FULL engagement or be disabled altogether and advises the driver that should this happen the procedure to follow is to pull over long enough for the rear linear clutch to cool off.

Toyota and Lexus have been notoriously lax with this type of advice so I suspect we will not see this CAUTION note in any Toyota or Lexus owners manual until maybe 2013.

While I am NOT a strong fan of the current RX's F/awd it can be made more functional than the new one. The current model uses a fully OPEN center diff'l that will allocate the engine drive torque 50/50 F/R just as long as both "ends" have equal, roughly equal, traction with the road surface.

The "secret" to making use of the current system is to assure that F/R roadbed traction is ALWAYS roughly EQUAL. I do that by installing all four tire chains in times of need.

The only option with the new system would be to "wire" the rear clutch fully closed and disable one of the front drive halfshafts. You would then have a RWD vehicle, ultimately more safe than the new F/awd RX350.

I have been seriously considering the purchase of a Mercury Mariner hybrid (now with VSC) and should I do so it would go immediately into the shop for a REMCO front halfshaft modification and I would "hot-wire" the rear clutch fully closed.

RWD but with part-time 4WD capability via manually engaging the REMCO halfshaft coupling device.

 

Are you brain dead? Do you not understand that this thread is about FEH and MMH and not Toyota or Lexus? Just because you are thinking of buying a vehicle does not mean that your assumptions of what Toyota or Lexus will or will not do bear any relevence to a FEH or MMH. I am not discounting the amount of time you have spent looking at the Toyota or Lexus vehicles but go post this in their threads because it surely relates there MUCH more than it does here. You sir, are a joke. At this point, all I can do is assume that you simply sit up there in the beautiful pacific west and dream up ways to irritate people. You obviously have a lot of knowledge but you have not demonstrated any practival experience with either the FEH or MMH. If you have questions about them post your questions but leave your speculation to yourself until you actually own and drive one. It really does no good to speculate how another vehicle, that is not even in production yet, might or might not relate to a completely different vehicle that you do not own or operate.

 

"The Ford manual WARNS that in this circumstance, linear clutch overheating, the system may go to FULL engagement or be disabled altogether and advises the driver that should this happen the procedure to follow is to pull over long enough for the rear linear clutch to cool off."

Does not exist in my hybrid manual or service manual. Since this statement(s) have not been documented in the FE Hybrid literature, treat it as what the elected officials say.

 

You're not looking closely, or well enough...It's there.

 

Leave it to Willard. He can't produce evidence on this site.

 

I fear I will regret this.

Note, the following quote has NOTHING to do with cold weather regenerative breaking, nor the anti-lock brake system.

From page 205 of the 2006 FEH Owner's Manual:

"During very extreme off-road events, the 4WD system has a heat
protection mode to protect itself from damage. If the system detects an
overheat condition, it will enter a locked mode. If the heat in the 4WD
system continues to rise in locked mode, it will disable itself. To exit heat
protection mode, simply stop the vehicle and allow it to cool for five

minutes with the key in the 3 (RUN) position."

Oh, and FWD is superior on snow and ice.

-J

 

My quote was from the 2009 Escape and Escape hybrid owners manual.

Purchased on line for $12.99