Notices
LS - 4th Gen (2007-2017) Discussion topics related to the current flagship models LS460, LS460L and LS600H

Transmission "lag" when decelerating

Thread Tools
 
Search this Thread
 
Old Aug 26, 2008 | 02:19 PM
  #1  
lexier's Avatar
lexier
Thread Starter
Driver
15 Year Member
 
Joined: Jun 2007
Posts: 57
Likes: 2
From: california
Default Transmission "lag" when decelerating

This is truely a great forum and thanks to ALL who have contributed to it.
It helped me to make a decission to buy a 2008 SWB. I have owned a 1994 LS400 and a 2003 LS430 and now love the LS460.

I have a question if anyone has noticed a problem with the LS460 pulling back or "lagging" when decelerationg - like the brakes are being applied, when they are not. I have given it 1000 miles, hoping that I would get used to it or the car would "learn" my driving habits. I do not drive it hard, and it seems to happens most in the 30MPH - 40MPH range. The dealer said that everything looks normal. Any thoughts?
Reply
Old Aug 26, 2008 | 02:30 PM
  #2  
Johnny's Avatar
Johnny
Pole Position
 
Joined: Mar 2007
Posts: 2,730
Likes: 26
From: Sakon Nakhon
Default

Your transmission has a mind of its own - literally. When your car decelerates, it will down shift by itself (as directed by its ECU), without braking or manual shifting by you. Most cars now have that feature, but on some cars it is more apparent than others, and the LS is one example. I notice it on mine as well, and if there was anything abnormal, it would show up on your dealer's computer's diagnostic check report.
Reply
Old Aug 26, 2008 | 02:47 PM
  #3  
lexier's Avatar
lexier
Thread Starter
Driver
15 Year Member
 
Joined: Jun 2007
Posts: 57
Likes: 2
From: california
Default

Thanks for your reply Burnaby. It just seems as if it does not "coast" very well when I lift my foot off the pedal at 40MPH , and as the speed drops
down to 30MPH, it frees up and seems to coast normal. Do you have the
same experience?
Reply
Old Aug 26, 2008 | 05:25 PM
  #4  
Stoks's Avatar
Stoks
Rookie
 
Joined: Sep 2007
Posts: 73
Likes: 1
From: OK
Default

I have an 07 LS460 SWB with 11k miles on it. My car coasts very easily. In fact, I find myself having to tap the brakes to slow it down while coasting down slight inclines in order to avoid speeding.

I have noticed that every once in a great while, the car seems to catch gears going down an incline and it doesn't coast as easily. But, that doesn't happen very often.

My understanding is that the car has been engineered to coast pretty easily in order to boost mileage, but I'm not certain about this.

My experience is definitely different than yours.
Reply
Old Aug 26, 2008 | 06:36 PM
  #5  
lucasb7's Avatar
lucasb7
Lead Lap
CL Folding 500,000
 
Joined: Aug 2007
Posts: 423
Likes: 1
From: CA
Default

It seems as though I heard something about it doing that when in the PWR mode. At least on the GS that is.
Reply
Old Aug 29, 2008 | 08:49 AM
  #6  
MythBuster's Avatar
MythBuster
Driver
 
Joined: May 2008
Posts: 171
Likes: 1
From: S.Arabia
Default

I have noticed the same when I use the power mode.

I use the power mode to reduce the coasting and save breaks.
Reply
Old Sep 6, 2008 | 11:51 AM
  #7  
joedaddy1's Avatar
joedaddy1
Racer
20 Year Member
Liked
Loved
Community Favorite
iTrader: (1)
 
Joined: Dec 2005
Posts: 1,981
Likes: 214
From: Orange County
Default

i have the same issue.. but not sure if it's normal.
Reply
Old Sep 6, 2008 | 03:50 PM
  #8  
Nospinzone's Avatar
Nospinzone
CL Community Team
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Mar 2007
Posts: 4,264
Likes: 481
From: MA
Default

I use the power mode to reduce the coasting and save breaks.

Myth, I'm not sure that is the wisest way to reduce wear on your brake pads. In the long run the extra wear and tear on your transmission may end up being more expensive. That's just an opinion, I can't back it up with solid evidence.
Reply
Old Sep 6, 2008 | 06:42 PM
  #9  
lexier's Avatar
lexier
Thread Starter
Driver
15 Year Member
 
Joined: Jun 2007
Posts: 57
Likes: 2
From: california
Default

I do not use the power mode and it still happens. When I get up to the
speed of 40mph, I then lift my foot off the gas and it drops to 30mph in
approx 10 - 12 seconds. I was able to drive another LS460 and it doesn't
drop to 30mph for at least 25 - 30 seconds. (this has been my minor test,
as it just doesn't fell correct) The dealer is trying to tell me that the car
needs to "learn" my driving habits, but I now have 1600 miles and no change.
They have already hooked my car up to the computer, and they say it is
under factory specs. I'm going to ask them to hook up the other car that
feels correct, and also my again, to see if there is anything that might
show up. By the way, I love this car and there is no wind noise!! I'm just
hoping that there is a solution for this "lag" issue.
Reply
Old Sep 6, 2008 | 07:25 PM
  #10  
Johnny's Avatar
Johnny
Pole Position
 
Joined: Mar 2007
Posts: 2,730
Likes: 26
From: Sakon Nakhon
Default

Originally Posted by lexier
The dealer is trying to tell me that the car
needs to "learn" my driving habits.
That's original... Where do they get these brush-offs?
Reply
Old Sep 13, 2008 | 12:17 PM
  #11  
lexier's Avatar
lexier
Thread Starter
Driver
15 Year Member
 
Joined: Jun 2007
Posts: 57
Likes: 2
From: california
Default

I just got a call from the dealer, they said that they test drove two LS460's that were in for other service issues, and that they both had the same symptoms that mine has. (As if it is normal and get over it) I'm wondering if any of you have had the problem. I just can believe it is normal. When I drove one of the new cars, it did not seem to do it. I have ask them to check with Lexus on a possible solution. Anyone else have any answers?
Reply
Old Sep 13, 2008 | 01:21 PM
  #12  
MythBuster's Avatar
MythBuster
Driver
 
Joined: May 2008
Posts: 171
Likes: 1
From: S.Arabia
Default

Myth, I'm not sure that is the wisest way to reduce wear on your brake pads. In the long run the extra wear and tear on your transmission may end up being more expensive. That's just an opinion, I can't back it up with solid evidence.
Sorry I did not see your comments, but it has to be common sense. You are correct if I push it too hard (Some times I do) .

The L 10 life of bearings is a function of load and RPM. Higher speed will defnatly reduce the bearings life.

But I try to stay within 3500 rpm which should not be too bad.
Reply
Old Sep 13, 2008 | 01:31 PM
  #13  
MythBuster's Avatar
MythBuster
Driver
 
Joined: May 2008
Posts: 171
Likes: 1
From: S.Arabia
Default

When I get up to the speed of 40mph, I then lift my foot off the gas and it drops to 30mph in approx 10 - 12 seconds
I will test mine to see how long it will take to drop from 40 t0 30

but you did not tell us what is the rpm at 40, and the rpm at 30.

I would think the gear will be at the 4th or third change at 40 m/h

-------------------

After my first post I start to look carfuly, I think it hapens in the early morning, but as the gear box oil heats up it does not do that any more. (I have to verify this though)

I just can believe it is normal
There must be away to reprogram the shifting points. You may ask the dealer if they can advance the shifting by 2% for example. (Just brain storming)
Reply
Old Sep 13, 2008 | 02:43 PM
  #14  
bitkahuna's Avatar
bitkahuna
CL Community Team
iTrader: (20)
 
Joined: Feb 2001
Posts: 80,785
Likes: 3,986
Default

Originally Posted by Nospinzone
I use the power mode to reduce the coasting and save breaks.

Myth, I'm not sure that is the wisest way to reduce wear on your brake pads. In the long run the extra wear and tear on your transmission may end up being more expensive. That's just an opinion, I can't back it up with solid evidence.
Originally Posted by MythBuster
Sorry I did not see your comments, but it has to be common sense. You are correct if I push it too hard (Some times I do) .

The L 10 life of bearings is a function of load and RPM. Higher speed will defnatly reduce the bearings life.

But I try to stay within 3500 rpm which should not be too bad.
Unless you guys plan to keep your cars for 200K mi. and beyond, you have nothing to worry about either way.

And brakes are cheaper than transmissions.
Reply
Old Sep 15, 2008 | 09:09 AM
  #15  
lexier's Avatar
lexier
Thread Starter
Driver
15 Year Member
 
Joined: Jun 2007
Posts: 57
Likes: 2
From: california
Default

Thanks MythBuster for your suggestion on advancing the shifting by 2%. I'll ask them if there is such an adjustment. I checked the RPM's.
40MPH = 1300RPM's then as it drops to 30MPH the RPM's drop to 1000, then it shifts (and frees up to a normal coasting) at 1200 RPM's. There is also the same type of drag when I bring the speed upto 30MPH and coast down to 20MPH. 30MPH = 1000RPM's and drops to 20MPH at 800RPM's then shifts and frees up at 1000 RPM's
Reply



All times are GMT -7. The time now is 12:14 PM.