AWD vibration coasting downhill around 60MPH
#1
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AWD vibration coasting downhill around 60MPH
During an extended drive of the new ride today, we noticed an intermittent vibration when coasting downhill around 60MPH. I popped it in neutral and the vibration disappeared completely. Also, it stayed vibration-free when placed back in Drive, without touching the gas. But as soon as throttle is applied and then you coast again, the vibration reappears.
This points to a condition that only happens when the torque converter is locked, which could be a vibration originating within the transfer case that once coupled to the engine via the locked torque converter uses the engine as a tuning fork, resulting in the vibration. The L-SB-0013-12 AWD Vibration TSB mentions an ECM recalibration, which likely changes the torque converter to unlock whenever you lift off the gas pedal. Is this correct?
I also remember reading about the other TSB, where the "magic expensive fluid" in the transfer case gets changed 3 times in rapid succession. This would address chattering clutches within the transfer case, eliminating vibration at the source vs. masking it by unlocking the torque converter. Does anyone have a link to that post?
We also noticed a misfiring sensation under light throttle conditions at around 40-50MPH. I'm wondering if this is in fact the transfer case clutch chatter issue also...since the 60k spark plug replacement has already been done. Thoughts?
This points to a condition that only happens when the torque converter is locked, which could be a vibration originating within the transfer case that once coupled to the engine via the locked torque converter uses the engine as a tuning fork, resulting in the vibration. The L-SB-0013-12 AWD Vibration TSB mentions an ECM recalibration, which likely changes the torque converter to unlock whenever you lift off the gas pedal. Is this correct?
I also remember reading about the other TSB, where the "magic expensive fluid" in the transfer case gets changed 3 times in rapid succession. This would address chattering clutches within the transfer case, eliminating vibration at the source vs. masking it by unlocking the torque converter. Does anyone have a link to that post?
We also noticed a misfiring sensation under light throttle conditions at around 40-50MPH. I'm wondering if this is in fact the transfer case clutch chatter issue also...since the 60k spark plug replacement has already been done. Thoughts?
#2
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L-SB-0023-11 was the other TSB with the fluid change, but it is older and only applies to 2008-2010. http://www.revbase.com/BBBMotor/TSb/...dPdf?id=168988
Here is the post on the transfer case fluid change 3x: https://www.clublexus.com/forums/ls4...vibration.html
Here is the post on the transfer case fluid change 3x: https://www.clublexus.com/forums/ls4...vibration.html
#3
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Update: SOLVED!
The dealer did a ton of work to diagnose and correct this issue, the latest (and most complex thing, it involved dropping the engine out!) completely eliminated the vibration. It is now a glass-smooth magic carpet at all speeds. I pick it up later today, will advise on what they did to kill the vibration dead. They did the 2 TSBs mentioned above (change xfer case fluid 3 times, recalibration) but those did not fix the problem - something else they did after that did the trick.
The dealer did a ton of work to diagnose and correct this issue, the latest (and most complex thing, it involved dropping the engine out!) completely eliminated the vibration. It is now a glass-smooth magic carpet at all speeds. I pick it up later today, will advise on what they did to kill the vibration dead. They did the 2 TSBs mentioned above (change xfer case fluid 3 times, recalibration) but those did not fix the problem - something else they did after that did the trick.
#5
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They replaced both front CV axles, and also replaced the CV support bearing in the right side of the oil pan. The bearing in the pan is visible in this example:
#7
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Yep, 6/70000 powertrain warranty covered it (the 3/100000 CPO would have also). It would have been pricey, as the powertrain had to be dropped out to do the bearing. So I also received a free coolant change, freon recharge, and oil change as part of the process.
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#8
LS AWD vibration while coasting - FIXED
They replaced both front CV axles, and also replaced the CV support bearing in the right side of the oil pan. The bearing in the pan is visible in this example:
I had same exact problem. Purchased Lexus Certified 2014 AWD LS460. Had vibration when coasting above 60mph. Dealer tried all TSB’s multiple times. I found Tec80’s solution of replacing both front axles. After a providing Tec80’s solution from this forum and discussions with dealer, and factory reps approval, dealer replaced both front axles. Work order stated excesive play in axle. Stated replaced with upgraded axles. Problem finallt FIXED. I want to thank Tec80 and this forum. Otherwise I do not think this would have been resolved.
I had same exact problem. Purchased Lexus Certified 2014 AWD LS460. Had vibration when coasting above 60mph. Dealer tried all TSB’s multiple times. I found Tec80’s solution of replacing both front axles. After a providing Tec80’s solution from this forum and discussions with dealer, and factory reps approval, dealer replaced both front axles. Work order stated excesive play in axle. Stated replaced with upgraded axles. Problem finallt FIXED. I want to thank Tec80 and this forum. Otherwise I do not think this would have been resolved.
#9
I had a 2011 LS 460L AWD and now a 2013 L AWD. Both cars I had to have both front axles replaced. The 2011 was somewhere around 30k miles and my current 2013 had axles replaced at 24k miles. Both times replaced under power train warranty. I’m not impressed with build quality. Maybe it is just AWD versions as RWD seems to be ok. Rides great now, no vibration. I think it still takes bumps a little rough, but not much I can do.
#10
Lexus Fanatic
Having had both the AWD car and the RWD car, I definitely prefer the RWD car
#12
Lexus Fanatic
Same here, and my RWD LS400 and LS430 were terrible in the snow. I was however really surprised by how sure footed my RWD LS460 was in the snow this past winter, traction control and VSC have really come a long way. Coming from an AWD LS460 directly comparing it within the same winter, for the climate around here I see no need to get the car in AWD.
#13
2014 LS 460 vibration issue
I bought recently certified pre owned with 50k miles and took it in almost immediately because of the vibration issue. They replaced the front axles and it seemed fine but today I'm feeling it again. Not sure if they replaced the support bearing on the oil pan like mentioned by Tec80 but I can ask. Very frustrating.
#14
I bought recently certified pre owned with 50k miles and took it in almost immediately because of the vibration issue. They replaced the front axles and it seemed fine but today I'm feeling it again. Not sure if they replaced the support bearing on the oil pan like mentioned by Tec80 but I can ask. Very frustrating.