T-SB-0300-08 Abnormal Metallic Knock Noise from Front of Vehicle

Discussion in 'Toyota Prius Service Bulletins - TSBs' started by Patrick Wong, Jan 13, 2010.

  1. Patrick Wong

    Patrick Wong DIY Enthusiast

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    This TSB shows that an engine mount may be the cause of a knocking sound coming from the front of the car, near the transaxle. The noise would happen when you go over a bump in the road.

    I have been noticing this sound from my 2004 for a while, when driving up or down on my driveway from the adjacent road. I replaced the front struts (which were quite worn, anyway) and the noise continued.

    The rubber bushings on the front sway bar look OK, so I might order the new engine mount and see if that helps. It is necessary to remove the inverter first, to gain access to this mount.
     

    Attached Files:

  2. usbseawolf2000

    usbseawolf2000 HSD PhD

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    The replacement simply added EPT Sealer in a new location. Wouldn't it be more cost effective to buy these adhesive rubber foam and tape it on it?

    The process involve removing the inverter. I wonder if it is a big job or how heavy it is....
     
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Well, I see that sealer is being used in a new location, but I thought the part itself was defective, thus causing the noise?? Why would the TSB want you to install a new part, if all that is required is more sealer?
     
  4. Flying White Dutchman

    Flying White Dutchman Senior Member

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    is a TSB not something that toyota needs to replace on toyotas cost?
     
  5. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Yes, only within 5 years or 60,000 miles. Otherwise the part retails $78.
     
  6. dogfriend

    dogfriend Human - Animal Hybrid

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    I think Hobbit was able to move the inverter to the side without draining the coolant. I wonder if this may be possible doing this repair?
     
  7. BigED

    BigED New Member

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    Crap. My '04 has just been diagnosed with this issue. I have a few prior threads where I've replaced most of the front suspension components, and the noise persists. I finally "broke down" and took it to a Toyota shop, and this is what they came up with.

    Anyone know if you really do need to drain the inverter? I'm pretty good at DIY, but essentially "unbolting the transmission" and moving it, I don't know if I'm up for that.

    Anyone have a perspective?
     
  8. dogfriend

    dogfriend Human - Animal Hybrid

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    Here is the link where Hobbit moves the inverter to the side while doing a transmission fluid change (not necessary, but he explains why he did it in the story).

    http://techno-fandom.org/~hobbit/cars/maint50k/

    Maybe Patrick can weigh in, if he replaced the engine mount?
     
  9. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I did not replace the engine mount, as the noise either went away or else I got used to it...

    However I think it would be necessary to remove the inverter fully, rather than try to juggle with it while also trying to replace the engine mount.
     
  10. mfa-prius

    mfa-prius Old member

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    I was hoping my noise was struts, but yesterday the dealer came up with this. The good news is, the dealer did say that there was no technical need for the repair, but the bad news was a $300 labor estimate. I was encouraged when I saw this thread, but discouraged by Patrick's last post, so I think I'll get used to the noise as well, or wait to combine this fix with some other operation requiring inverter removal.
     
  11. Jodenpenting

    Jodenpenting New Member

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    I'm pretty good at DIY, but essentially "unbolting the transmission" and moving it, I don't know if I'm up for that.
     
  12. hpoohhui

    hpoohhui New Member

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    I have a 07 Prius making some weird noise... here is a youtube video with the noise, could someone confirm?

     
  13. rocketrob

    rocketrob Member

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    This is the best video demonstration I've seen so far of the front end 'rattle/clunk' noise persistant on my '07 (manuf. 11/06). I would note that the noise is much more pronounced not just when rolling over speed bumps but with the brake pedal slightly engaged.

    hpoohhui: How long has your Prius had this noise? Have you road tested with a dealer mechanic?

    There are several threads on this topic, one that I have started. I have had the TSB pertaining to this thread performed on my Prius but it unfortunately did NOT eliminate the noise. The suspension checks out fine, as do all other mechanicals. I have not gotten any resolution on this.
     
  14. cwerdna

    cwerdna Senior Member

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    Yep, the clunk/crunch sounds in hpoohhui's video sound very much like what my 06 makes. I'm not sure if it's 100% consistent over speed bumps but I think I hear it every time when I pull into my driveway.

    It's been doing it for a long time and I think I was already out of warranty by the time I saw the TSB. :( So, I haven't bothered to do anything about it.

    I notice it says 2.1 for time, which I assume = hours. That's not going to be cheap.
     
  15. hpoohhui

    hpoohhui New Member

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    I actually purchased this Prius not long ago (CPO) and i heard this noise whenever i pull into my driveway since day one. Yes, the noise is more pronounced with the brake pedal slightly engaged.

    I did road test the car with a dealer mechanic but he said that the noise is "normal" because there are 2 other Prius that he tested also produce the same noise. I will go back and have them look at the TSB and see what they wanted to do.
     
  16. mfa-prius

    mfa-prius Old member

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    Noises are NOT normal. Sounds like struts to me. In my case, all struts were alleged to be fine (i.e., no oil leaks), by 2 dealers, one of whom suggested the TSB. Ultimately, at 95,943 miles, a 3rd dealer found that the bushings at the top of the front struts were all wallowed out, allowing the strut to wobble and clunk. Replacing the front struts solved the problem. But a severe rattling-over-railroad-crossings noise persisted. Also, a humming/whirring noise developed, only noticeable on a quiet road. It varied with speed, and changed character at 40, 50, and 60 mph. The same dealer said that the front tires were badly cupped, but couldn't say why. I said the tires had just been rotated, and we experienced an AHA! moment. The REAR struts were also bad, which had caused the tire cupping. Also, the rack & pinion, half-shaft & yoke assy were deemed to be shot and causing the railroad-track rattle. Bottom line for me was slightly over $4K for everything (including 4 new tires), and a note to self: replace the struts proactively at 60K miles or so, which I think others on the forum have recommended. Not thrilled about the failure of the steering components, and very not thrilled about the Yokohama tires the dealer recommended.
     
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  17. My1Project

    My1Project Junior Member

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    Patrick, Thanks for posting the TSB. I've recently replaced the lower, control arms, ball joints, struts and mounts, stabilizer links and bushings and have the clunk going over large bumps, but the ride is good and the front end feels stable. I'm going on a road trip and will order and replaced the LH engine mounting bracket when I get back. I don't think this is an item that has a catastrophic failure as that would require a recall.
     
  18. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I agree.

    Please post photos comparing the old mount to the new and showing the amount of disassembly needed for access, and let us know if the replacement helped the clunk that you have observed.
     
  19. Jmack111

    Jmack111 Member

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    End of strut Springs in the wrong you finger to find the end there a notch on the bottom side the end spring sit in to fix it take apart strut and put the end of the spring in the notch and clamp it while you put it back together

    Posted via the PriusChat mobile app.
     
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  20. garglo

    garglo Member

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    I have ignored the noise as long as I can. Has anyone had success with this TSB?
     
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