Thump from P to R & from R to D
03-09-15, 07:22 PM
#1
Lexus Test Driver
Thread Starter
Thump from P to R & from R to D
I had mentioned this in another thread but I figured I'd post it here so that more eyes could see it.
I first noticed this recently as my wife was pulling out of the driveway into the street...
The car wasn't cold, as it had been running for a bit over 5 minutes, warming up. My driveway slopes a bit towards the street and also has a dip/hump at the end of it. As she pulled out in R from P, I heard a thump. I also hear a noise which sounds like the brakes engaging. So in order, brakes engaging, shift from P to R, the thump then as it backs up and turns into the street, there's a slight, faint grind noise. As the car stops to go from R to D, it thumps again. But as it goes into drive and pulls away..smooth as butter and quiet.
I've heard and read that it's possible motor mounts.
I'm wondering if the light grinding is the actuator...or perhaps dried out bushings in the control arms...
Also read the possibility of the trans going bad, which I highly doubt, but who knows.
My plan is to call Lexus in the morning and see if I can be squeezed in.
I first noticed this recently as my wife was pulling out of the driveway into the street...
The car wasn't cold, as it had been running for a bit over 5 minutes, warming up. My driveway slopes a bit towards the street and also has a dip/hump at the end of it. As she pulled out in R from P, I heard a thump. I also hear a noise which sounds like the brakes engaging. So in order, brakes engaging, shift from P to R, the thump then as it backs up and turns into the street, there's a slight, faint grind noise. As the car stops to go from R to D, it thumps again. But as it goes into drive and pulls away..smooth as butter and quiet.
I've heard and read that it's possible motor mounts.
I'm wondering if the light grinding is the actuator...or perhaps dried out bushings in the control arms...
Also read the possibility of the trans going bad, which I highly doubt, but who knows.
My plan is to call Lexus in the morning and see if I can be squeezed in.
03-09-15, 07:37 PM
#2
Lexus Fanatic
I had mentioned this in another thread but I figured I'd post it here so that more eyes could see it.
I first noticed this recently as my wife was pulling out of the driveway into the street...
The car wasn't cold, as it had been running for a bit over 5 minutes, warming up. My driveway slopes a bit towards the street and also has a dip/hump at the end of it. As she pulled out in R from P, I heard a thump. I also hear a noise which sounds like the brakes engaging. So in order, brakes engaging, shift from P to R, the thump then as it backs up and turns into the street, there's a slight, faint grind noise. As the car stops to go from R to D, it thumps again. But as it goes into drive and pulls away..smooth as butter and quiet.
I've heard and read that it's possible motor mounts.
I'm wondering if the light grinding is the actuator...or perhaps dried out bushings in the control arms...
Also read the possibility of the trans going bad, which I highly doubt, but who knows.
My plan is to call Lexus in the morning and see if I can be squeezed in.
I first noticed this recently as my wife was pulling out of the driveway into the street...
The car wasn't cold, as it had been running for a bit over 5 minutes, warming up. My driveway slopes a bit towards the street and also has a dip/hump at the end of it. As she pulled out in R from P, I heard a thump. I also hear a noise which sounds like the brakes engaging. So in order, brakes engaging, shift from P to R, the thump then as it backs up and turns into the street, there's a slight, faint grind noise. As the car stops to go from R to D, it thumps again. But as it goes into drive and pulls away..smooth as butter and quiet.
I've heard and read that it's possible motor mounts.
I'm wondering if the light grinding is the actuator...or perhaps dried out bushings in the control arms...
Also read the possibility of the trans going bad, which I highly doubt, but who knows.
My plan is to call Lexus in the morning and see if I can be squeezed in.
03-09-15, 07:41 PM
#3
Lexus Test Driver
Thread Starter
Another item to check is the flex plate (also called a flex disc). This essentially, is a universal joint in the driveshaft and made of hard rubber. When they wear, they slacken and cause a thunk. This is a common problem in BMW's but haven't heard of any issues in the LS. Still, worth a look. They're cheap and fairly easy to replace.
Now, should I ask about that/mention that before hand or just tell them about my issue and see what they come back with?
03-09-15, 07:48 PM
#4
Lexus Fanatic
Well, if you're comfortable getting under your car, you could do a visual inspection, but to be honest, that may not fully tell you it's worn. On my 7 series Beemer, it SEEMED ok, but when I removed it, the rubber was cracked and sloppy. Once I replaced it, the clunks (especially when the trans geared down when coming to a stop), dissapeared. Made the car feel new again.
Last edited by roadfrog; 03-09-15 at 07:51 PM.
03-09-15, 07:58 PM
#5
Lexus Test Driver
Thread Starter
Well, if you're comfortable getting under your car, you could do a visual inspection, but to be honest, that may not fully tell you it's worn. On my 7 series Beemer, it SEEMED ok, but when I removed it, the rubber was cracked and sloppy. Once I replaced it, the clunks (especially when the trans geared down when coming to a stop), dissapeared. Made the car feel new again.
Last edited by CRowe14; 03-10-15 at 11:39 AM.
03-09-15, 09:43 PM
#6
I don't have a clue what is causing that, but I doubt it is the control arms. Hopefully when the dealer gets it up on a lift any visible problems like motor mounts or the flex plate (I didn't even know the car had one) will be evident. Otherwise it does sound like a transmission problem.
Keep us posted.
Keep us posted.
03-09-15, 11:11 PM
#7
Lexus Fanatic
I have no issues at all getting beneath the car, I just have no idea where to look! I can find out though, Google is great that way. Silly question though...while driving and hearing down it's fine, it's only when switching gears...would this still possibly be a culprit?
As for whether it's the culprit....no idea. Sure is cheaper than a trans tear-down though.
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03-10-15, 07:37 AM
#9
Lexus Test Driver
Thread Starter
***Update***
I am currently at the dealership and have gone through a preliminary inspection with the Master Techs and Service Manager. We went outside so that I could duplicate the issue for them to hear. They both surmised that It wasn't the transmission, but the brakes/pads doing a combination of engaging/disengaging and shifting. They say it's normal, as the LS is very heavy and the pads are quite large on this car. I also asked about the actuator, as there is a noise when going into gear and when placing the car into P. I duplicated that as well. He said that it didn't sound like the actuator but a torque bolt that sometimes needs to be tightened down a bit tighter than spec. I went ahead and asked them if they minded doing a full look over of the vehicle, simply for peice of mind and they obliged without a a single hitch.
The tech and Service Manager said the miles are pretty low for a car this age and that since I just bought it and the service history is solid, I should have no reason to be overly worried about anything' at this point. I asked if they could pay special attention to the control arms, brakes, the actuator and everything else... They both agreed they desired for me to be happy with the product and will do what they can, even though I didn't purchase it from them, but just because it's a Lexus product.
Something else he told me that was interesting...
We got into a conversation and began speaking about the pompous and entitled attitudes of certain people. And he states how some Lexus engineers are very, very difficult to deal with and insist that their way is the only way, even though there may be or are solutions that are more cost effective, I.e.: control arm bushings.
He said that they refuse to adress the issue correctly regarding the design, as it's a known issue especially with the LS because it's so heavy. But he did say that these cars, especially the LS, up to about 100-120k are pretty much rock solid. And I think that's largely why we have decided to purchase the cars we have.
Will report back once the car is lowered and the results from the inspection are revealed.
The tech and Service Manager said the miles are pretty low for a car this age and that since I just bought it and the service history is solid, I should have no reason to be overly worried about anything' at this point. I asked if they could pay special attention to the control arms, brakes, the actuator and everything else... They both agreed they desired for me to be happy with the product and will do what they can, even though I didn't purchase it from them, but just because it's a Lexus product.
Something else he told me that was interesting...
We got into a conversation and began speaking about the pompous and entitled attitudes of certain people. And he states how some Lexus engineers are very, very difficult to deal with and insist that their way is the only way, even though there may be or are solutions that are more cost effective, I.e.: control arm bushings.
He said that they refuse to adress the issue correctly regarding the design, as it's a known issue especially with the LS because it's so heavy. But he did say that these cars, especially the LS, up to about 100-120k are pretty much rock solid. And I think that's largely why we have decided to purchase the cars we have.
Will report back once the car is lowered and the results from the inspection are revealed.
03-10-15, 08:26 AM
#10
Lexus Test Driver
Thread Starter
Well, all is well, but I need front pads and rotors.
The rear rotors can be cut, but recommend rear pads. Fronts are at 4/32, rear is 5/32. He said my sensors are fine at this point, but if the are effected, they'll need to be replaced, which I've read before.
Price: $870.08
So everyone..what are your choices for good, aftermarket rotors and pads??
And if the job isn't anything crazy, I'll be doing the replacement myself.
The rear rotors can be cut, but recommend rear pads. Fronts are at 4/32, rear is 5/32. He said my sensors are fine at this point, but if the are effected, they'll need to be replaced, which I've read before.
Price: $870.08
So everyone..what are your choices for good, aftermarket rotors and pads??
And if the job isn't anything crazy, I'll be doing the replacement myself.
03-10-15, 08:40 AM
#11
Check under the "Brakes" section in the DIY sticky for lots of info and recommendations.
Glad it wasn't your transmission.
03-10-15, 11:22 AM
#12
Unfortunately, many (most?) cars with floating calipers will click, clunk, chatter, etc, etc when the brakes are applied and released. Drives me nuts, but I own several cars that have done/do this. The dealers will clean and apply a thick heat-proof grease to the slide pins, which helps, while the car is under warranty but after that, you're on your own. 
03-10-15, 11:46 AM
#13
Lexus Test Driver
Thread Starter
You know it just kills me when these guys say an unusual noise/condition is normal. I always recommend you ask to drive one of their demos to see if that car does it. Betcha it doesn't.
Check under the "Brakes" section in the DIY sticky for lots of info and recommendations.
Glad it wasn't your transmission.
Check under the "Brakes" section in the DIY sticky for lots of info and recommendations.
Glad it wasn't your transmission.
I did think it strange though because before the inspection, they considered it normal and weren't really going to take any further action, but upon an inspection-that I requested, it was found that I need new pads/rotors.
The next time Im at the dealership, i'll sit and shift in a demo...see what happens.
Thanks Nospinzone, and indeed, very, VERY glad it wasn't my trans!
03-10-15, 11:57 AM
#14
Lexus Test Driver
Thread Starter
Unfortunately, many (most?) cars with floating calipers will click, clunk, chatter, etc, etc when the brakes are applied and released. Drives me nuts, but I own several cars that have done/do this. The dealers will clean and apply a thick heat-proof grease to the slide pins, which helps, while the car is under warranty but after that, you're on your own.
One thing is certain though, I will be replacing the pads and front rotors as to not tear up the sensors!
03-10-15, 01:25 PM
#15
Pole Position
Unfortunately, many (most?) cars with floating calipers will click, clunk, chatter, etc, etc when the brakes are applied and released. Drives me nuts, but I own several cars that have done/do this. The dealers will clean and apply a thick heat-proof grease to the slide pins, which helps, while the car is under warranty but after that, you're on your own.