Thump from hybrid (like a bass drop)

[DWN2RTH]

I've had the LX for four days now and it's been bittersweet. The ride is exceptional and the looks of the OT in Earth is absolutely amazing and eye catching. The bitter part is that every time the vehicle is slowed, or stopped and at idle, the engagement of the gas motor causes a thump that sounds like a bass drop in music. It's often louder than the actual bass in my music. And it's not just the sound, when this occurs during deceleration, there is a leaching feeling like the brakes temporarily fade and not it doesn't stop in a linear fashion (jerky). Took to the dealer, they said it's normal. But............if that's the case, then why doesn't the Sequoia or Tundra with the iForce do the same thing?? I drove several before this purchase and can definitely say that I have never felt or heard this thump in any of the other 700's or Toyotas.

Has anyone else experienced this? If so, what were you told or what was the fix?

 

[ShottsCruisers]

Hmm...2500 miles on mine. I do get the various sounds this baby makes. Varies by motor on or off, idle vs step on the gas, blah blah. None of the sounds bother us at all because overall the thing is super quiet and smoooooth. That said...when we're idling for some time the motor will kick in. Most of the time the noise (yes, lower freq) is slight. You simply hear it start. But every now and then it will boom when the motor kicks in at idle. Not sure why...but it's random and it doesn't bug us.

 

[DWN2RTH]

Thanks for the info. Mine was pretty serious and it also caused a bit of inconsistencies in braking. I returned it for a full rewind of the deal two days after purchase and after an inspection from service, which as expected said it was “ normal”. It was really hard as I love the look and quiet of the vehicle overall.

Back to shopping.

 

[ShottsCruisers]

Thanks for the info. Mine was pretty serious and it also caused a bit of inconsistencies in braking. I returned it for a full rewind of the deal two days after purchase and after an inspection from service, which as expected said it was “ normal”. It was really hard as I love the look and quiet of the vehicle overall.

Back to shopping.

Oh ya...you mentioned braking. Hmmm...no issues with ours.

 

[henke]

Yes, mine does too. But, it's no more loud than other low frequency noises from when you run over a bump or something similar.

I just notice it more because I subconsciously associate it with my actions controlling the engine. Otherwise it fades into the background for passengers.

It's also strange that it doesn't seem to happen with the auto stop start with the 600.

Not a deal breaker for me, but maybe they'll come out with a muffler or a diffuser or something...

 

[ShottsCruisers]

The LX600 doesn't do this because it simply starts with a starter like any other vehicle. The 700h engine starts from the hybrid system/motor, thus the difference (though not sure why this would not be as smooth).

 

[Tangopapa]

We just got a slightly used 2025 LX 700h Overtrail with 6K miles and are now noticing the same thing....it sound like a low thud when accelerating and happens every time....we did not noticed it during our test drive but that was very brief....but now we definitely notice it and it happens every time we accelerate , we normally accelerate gently so the sound is quite noticeable and the best way to describe it is a low thud.

Checking the threads, people have mentioned loose spare tire , jack , tools.....well I went and checked all of that and all of those are very well secured so that is not the source of the thud when accelerating....going to take it into the dealer for inspection.

 

[El Chorizo]

We just got a slightly used 2025 LX 700h Overtrail with 6K miles and are now noticing the same thing....it sound like a low thud when accelerating and happens every time....we did not noticed it during our test drive but that was very brief....but now we definitely notice it and it happens every time we accelerate , we normally accelerate gently so the sound is quite noticeable and the best way to describe it is a low thud.

Checking the threads, people have mentioned loose spare tire , jack , tools.....well I went and checked all of that and all of those are very well secured so that is not the source of the thud when accelerating....going to take it into the dealer for inspection.

Please let us know what they find out!

 

[Tangopapa]

Took it to the dealer - had a mechanic ride with me.

He said the sound is normal. It's basically whoosh of air going into the engine/turbos ...bit like drawing air from a straw. He said its not a hybrid thing...

If that is the case , then pretty much all new LX 600/700h should be having that sound ...is a low/faint thud on initial acceleration....can anyone else confirm this sound.

 

[El Chorizo]

Took it to the dealer - had a mechanic ride with me.

He said the sound is normal. It's basically whoosh of air going into the engine/turbos ...bit like drawing air from a straw. He said its not a hybrid thing...

If that is the case , then pretty much all new LX 600/700h should be having that sound ...is a low/faint thud on initial acceleration....can anyone else confirm this sound.

Can you get a video perhaps?

 

[ShottsCruisers]

It's NORMAL folks. When the electric battery triggers the engine to start there is a lower-pitch thug as it starts. IF it does this when the engine is RUNNING then I'd have somebody lube the driveshaft zerks (EASY) to eliminate that being an issue. Shouldn't be needed at 7K miles but it's a 2-minute fix.

 

[El Chorizo]

It's NORMAL folks. When the electric battery triggers the engine to start there is a lower-pitch thug as it starts. IF it does this when the engine is RUNNING then I'd have somebody lube the driveshaft zerks (EASY) to eliminate that being an issue. Shouldn't be needed at 7K miles but it's a 2-minute fix.

First time I've heard of a Zerk fitting, had to google it!

 

[ShottsCruisers]

Drive shaft thump. When not lubed is can stick a bit then give and THUMP.

 

[007 700]

We just got a slightly used 2025 LX 700h Overtrail with 6K miles and are now noticing the same thing....it sound like a low thud when accelerating and happens every time....we did not noticed it during our test drive but that was very brief....but now we definitely notice it and it happens every time we accelerate , we normally accelerate gently so the sound is quite noticeable and the best way to describe it is a low thud.

Checking the threads, people have mentioned loose spare tire , jack , tools.....well I went and checked all of that and all of those are very well secured so that is not the source of the thud when accelerating....going to take it into the dealer for inspection.

I’ve had mine for two weeks and same thud happens as I accelerate. I too ensured everything was secure including jack, battery, tire tools, third row seats (head rests are loose in down position but I doubt they could create such a large thud), spare tire is secure too.

 

[snowman69]

The thump is obviously not good. Good thing i just put a non refundable deposit/order on a 26. Let you all know in dec

 

[Tangopapa]

Can you get a video perhaps?

I will try to capture the sound and video when I have time...sorry been traveling and not sure if it will be loud enough to hear above the road noise.

 

[Tangopapa]

It's NORMAL folks. When the electric battery triggers the engine to start there is a lower-pitch thug as it starts. IF it does this when the engine is RUNNING then I'd have somebody lube the driveshaft zerks (EASY) to eliminate that being an issue. Shouldn't be needed at 7K miles but it's a 2-minute fix.

It happens on accelerate from stop, and its not the battery triggering the engine , which is a different sound.

 

[Tangopapa]

I am not completely convinced on the Lexus mechanics answer and want to verify.

Can someone explain how this works "IF it does this when the engine is RUNNING then I'd have somebody lube the driveshaft zerks (EASY) to eliminate that being an issue. "

The specific condition under which sound occurs is when the car is normal accelerating from a stop....and happens a fraction of a second after the vehicle starts moving (almost like something is moved by the forward momentum of the car and hitting something). This sound is different from when the engine kicks in due to autostart/stop. It occurs when engine is already running and you normal accelerate then a fraction of a second later there is a dull low volume thump sound....the sound is consistent in nature and I dont think it varies with how hard you accelerate so it is likely not being something loose in the car and bumping back due to forward momentum of the car. Normally, if something was loose, the thud timing and volume would vary ever so slightly based on how you accelerate....

But I want to understand this driveshaft zerks thing....and under the specific lens of knowing that the sound occurs just a fraction of the second after the car starts to move.