dthouston

Just bought a pre-owned 2012 LS 460L AWD with just over 50K miles on it. It's my third LS (all bought pre-owned), and it's head and shoulders nicer than my '90 and '99 LS'es (which I drove 310K and 270K miles in Houston traffic)!

After driving the "new" LS for about a month, it's clear there is something very strange going-on with the drive-train and/or brakes. Here's the symptoms...

1st problem...

At 60 mph, I let off the accelerator AND off the brake and let the car "coast down"... It slows down as expected until it gets to about 35 MPH, and then it feels as if I were applying brakes (even though I'm NOT). It slows down RAPIDLY between 35 to about 22 mph. Then at 22 mph it seems to "release" and the deceleration returns to a more gradual amount. It's almost like the transmission or drivetrain down-shifted into a lower gear between 35 and 22 mph (causing more deceleration) and then shifted into neutral at about 22 mph. However, I've watched the tach, and the engine revs don't indicate that the transmission has down-shifted. The engine revs remain at what you would expect for a car that's coasting to a stop. So whatever is going-on isn't "noticed" by the engine. And so I assume it's a problem in the transmission, diff(s) or even the brakes (even though I'm not applying the brakes).

2nd problem (maybe related to the 1st)...

When crawling along at 2 to 5 mph in very heavy stop-and-go traffic (a typical morning commute) it's almost impossible to come to a gradual, smooth stop. At very low speeds, the brakes seem to be "all off" or "all on".

Has anyone else seen these symptoms? I'm guessing that it's an issue with the AWD - maybe the "center diff" or something related. Either that, or the brakes are spontaneously applying themselves.

But is it a problem or simply part of the normal operation? And is there any additional/recommended service for the AWD, especially considering it now has 50K miles on it???

Thanks in advance!

DadCat

comotiger

Hello Dadcat, congrats on your recent acquisition of a 4LS. Based on your experience with the LS, you have truly enjoyed the fruits of this highly reliable automobile. It would be great to see inside and outside pics of your car.

For the 1st "problem", my car has done that occasionally, as if it downshifted into too-low a gear while coasting, but it is so rare that I have not investigated it carefully. But your guess of a transmission issue seems reasonable. Maybe the system just needs an update. As for the 2nd "problem", are you saying the brakes are grabby? It is a common occurrence with this car, and takes some getting used to. Some folks have noticed that the grabbiness goes away after switching to Centric rotors.

Since you have a pre-owned (CPO?) car, just have the dealer take a look. It appears that you are experiencing these issues all the time, so they must be easy to replicate.

dthouston

Thanks! I looked for a CPO 2012 for a long time before I found this non-CPO at a Mercedes dealer. But I did buy a warranty, which should cover the repairs (unless it's brake pads). I'll give it a few months and then take it to a Lexus dealer and have them service the trans/diffs and look at the brakes. What are Centric rotors?

I wanted a 2012 because I'm not a big fan of the hour-glass grill they introduced in 2013 (not to criticize your 2014 - it's just a matter of tastes).

BTW: my 2012 is also Obsidian with Black leather. So I think we mostly have the same taste!

DadCat

Nospinzone

Long shot, but is the car equipped with the pre-collision system or radar cruise control?

As to the braking, comotiger is right about the brakes being grabby. I remember when I took a test drive before I bought my car. My wife was in the back seat and she asked me why I was stomping on the brakes. I said I wasn't, its just that they were so much touchier than my Infiniti Q45a.

sktn77a

iTrader: (2)

Whatever it is, sounds like a trip to the Lexus dealer and maybe an ECU re-flash for #1 and a check of the various electronic brake systems for #2.

Tec80

Try bumping it into neutral just after lifting off the throttle and see if it still behaves oddly. That will narrow the issue down to brakes or driveline dragging vs. a transmission issue. Once that's determined, you will have more ammo to inform the technician where to look first.

Tec80

And brake grabbiness is an issue with the OEM brake pads. Install Akebono ACT1282/1283 brake pads and the problem will magically disappear.

comotiger

Centric is a brand name. Many folks here have had good experience with their rotors and pads. Check the Rotor and Brake threads for more discussion. Tec80 recommends Akebono pads. Looks like they are both better than the OEM rotor/brake pads to minimize grabbiness.

I wasn't a fan of the monster grille on the 2013+, but it has grown on me. In fact I had a 2012 SWB for several months before upgrading to the 2014 LWB for all the goodies (BSM, RCTA, DRCC, LKA, UltraLux...), some of which are not available pre-2013 (BSM, RCTA).

Welcome again, and look forward to the pics. Sounds like a great car and buy!

sapstar66

I have the exact same car as you.

It's a know issue for the AWD manufactured in 2012. Those drive axles are not properly balanced, creating the vibration decelerating. You can test this by putting the car in neutral as it does it. If it disappears, you found it!

Both my front axles were changed under warranty. They fight it a bit, cuz it's a costly repair, but they will do it.

droclex

I believe that this thread will be helpful for the OP:
https://www.clublexus.com/forums/ls-...30-40-mph.html

My '13 vibrated significantly while decelerating at highway speeds. I had the front driver side axle replaced by the dealer under warranty. Smooth as silk now!

roadfrog

As stated by others above, switching my rotors and pads to Centric premium completely eliminated my grabby brakes. They are now nice and linear and smooth.
Get a transmission flush from your dealer. It's good maintenance and the dealer can reflash your trans ECU at the same time.

FatherTo1

Chris, I understand braking is smoother for those that went the Centric route. Why is that exactly? I can see how different composition can affect squealing and/or amount of brake dust, but how do different rotors and brake pads eliminate the grabbiness? I am glad it does, I just don't understand the why please.

roadfrog

Perhaps the way I worded my post indicates that the Centric parts were the reason, but what I meant was that replacing the parts in general were the cause of improved braking. I was just giving kudos to the Centric brand in general as they perform well and seem to be of high quality. They also happen to be priced well. Whether the elimination of grabbiness is directly related to the pad composition or the replaced hardware (springs, clips etc), I don't know, but replacing everything has completely eliminated the grab and everything is buttery smooth now. Very linear.

dfkd

As I understood it, the default OEM brake pads offer a "high friction" compound that's optimized for maximum braking. The tradeoff seems to be higher dust and noise, and at low speed, the grabbiness most of us despise.
There's apparently also a "low dust" OEM pad option that would be easier on those negatives while sacrificing some of that grabbiness (aka effective braking force).

In my last few cars, I went to ceramic brake pad compound pads to chose a different set of compromises.
Ceramics tend to brake "smoother" and with less dust.
I've found that they tend to be noisier/grabbier when they're cold (as in winter cold).
That all goes away once you've done a bit of braking or once the engine heat has warmed the front end.

I've had my 460 a month now and can't wait to get the OEM pads out and some ceramics in.
Soon...

FatherTo1

Thank you, dfkd! That makes a lot of sense. My Centric parts should arrive Thursday. Our mechanic says I have maybe 5,000 miles left on the current front brakes but I think I will replace all corners as soon as the parts arrive. We took a trip out to a daffodil farm today and I'm getting better at modulating the OEM brake pads but still not as smooth and linear as our old LS 430.

I remember when ceramic pads were only on exotic cars. That was back in the 90s. It feels special putting ceramic pads on the LS, even if it's more commonly available now. I'll post back with my experience and hope it matches the positive experience you and others have had.