Sign In Join 



2009 Lexus RX 350

89 messages,  Last post on Nov 22, 2009 at 3:38 PM

You are in the Lexus RX 300/330/350 Forum. Your Hosts are steve_ & tidester

What is this discussion about? Lexus RX 350, Automotive News, SUV


Messages Page 7 of 10
1
...
4
5
6
7
8
9
10
Prev
Next
Last
Go To Msg #
Search This Discussion

#54 of 89
Re: transmission problem with brand new RX 350 [jym2009] by wwest
Jan 14, 2009 (1:50 pm)
Reply

Replying to: jym2009 (Jan 12, 2009 3:44 pm)

If they haven't figured out a fix for the 2010 RX350 you can make a sure bet that it still exists in the 2009 RX350.
 
Below quote is directly, word for word, from the 2010 RX350 factory manual set.
 
"The TCM determines the gear that is to be selected when the accelerator pedal is released (released completely) in accordance with the way the accelerator pedal is released (quickly or slowly) during deceleration. In this way, unnecessary upshifts are prevented during deceleration, matching the driver's intentions. In addition, unintended downshifts are prevented when accelerating the vehicle again, achieving smooth acceleration."
 
So, unless you can learn to abide by the above rules as to how you "manage" the accelerator pedal the 1-2 second downshift delay will remain a potential problem.
#55 of 89
Re: transmission problem with brand new RX 350 [wwest] by wwest
Jan 14, 2009 (1:54 pm)
Reply

Replying to: wwest (Jan 12, 2009 5:17 pm)

"..Have you considered holding out for a 2010 RX350...??"
 
I take that suggestion BACK...!!
 
The 2010 RX350 (and the Toyota Venza) F/awd system was adopted from the Ford Escape/Mariner/Tribute design and is WORSE than the previous RX F/awd system by a WIDE measure.
#56 of 89
Just leased in NJ by richneedsaleas
Jan 14, 2009 (1:58 pm)
Reply
MSRP $46K with Navi
10k miles year, $800 out the door, $459/mo incl CT Tax
Thanks to everyone on here for sharing their experiences
#57 of 89
Re: transmission problem with brand new RX 350 [wwest] by avery1
Jan 14, 2009 (4:35 pm)
Reply

Replying to: wwest (Jan 14, 2009 1:54 pm)

wwest can you elaborate on this Ford system and why it is worse?
#58 of 89
Re: transmission problem with brand new RX 350 [avery1] by wwest
Jan 15, 2009 (12:57 pm)
Reply

Replying to: avery1 (Jan 14, 2009 4:35 pm)

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.
#59 of 89
Re: transmission problem with brand new RX 350 [avery1] by wwest
Jan 15, 2009 (1:09 pm)
Reply

Replying to: avery1 (Jan 14, 2009 4:35 pm)

Assuming I keep my '01 F/awd RX300 until the transaxle (prematurely) fails, I will rebuild the transaxle but modify the drive system to R/awd. Now at ~75,000 miles.
 
Remove the front drive spider gear from the center diff'l, weld the rear drive spider gear to its side gear, install a VC from the '99 or '00 RX300. SOLID coupling to the rear driveshaft and only VC, Viscous Clutch, coupling to the front drive.
 
R/AWD RX300...!!
#60 of 89
Re: transmission problem with brand new RX 350 [wwest] by bodble2
Jan 15, 2009 (1:52 pm)
Reply

Replying to: wwest (Jan 15, 2009 12:57 pm)

This may be a silly question, but what is "OAT"?
#61 of 89
Re: transmission problem with brand new RX 350 [wwest] by bodble2
Jan 15, 2009 (1:53 pm)
Reply

Replying to: wwest (Jan 15, 2009 12:57 pm)

This may also be a silly question, or at least a lazy question, but does the new Venza have the same AWD system as the 2010 RX350?
#62 of 89
Re: transmission problem with brand new RX 350 [bodble2] by wwest
Jan 15, 2009 (6:03 pm)
Reply

Replying to: bodble2 (Jan 15, 2009 1:52 pm)

OAT, Outside Air Temperature.
 
And yes, it appears that the new Venza and the 2010 RX350 share the very same F/awd system.
#63 of 89
Re: transmission problem with brand new RX 350 [wwest] by bodble2
Jan 15, 2009 (6:23 pm)
Reply

Replying to: wwest (Jan 15, 2009 6:03 pm)

Thanks, Willard. You're The Man when it comes to AWD systems! I don't pretend I understand most of what you try to tell us. But I know you like BMW's X-drive, Acura's SH-AWD, and you're not a fan of the re-active, FWD-biased systems. Which other systems out there do you like?

Messages Page 7 of 10
1
...
4
5
6
7
8
9
10
Prev
Next
Last
Go To Msg #
Search This Discussion
To POST a message, please Sign In.

New? Join Now!

Forum Tools

Please sign in.
Email Address:

Password:

Forgot Password?

Search Forums

Enter Keyword(s)

Advanced Search

Browse by Vehicle



View All Vehicles
Advertisement
Ask the Community
See What People Are Asking

Browse by Board

Browse by Topic


View All Topics
Advertisement