High frequency vibration

[sony]

@nlspace : I really like how you think. They said to lubricate "the entire (front or rear) wheel hub bearing surface". I think you have a point about the wheel bearings preload. The scary part here is that this preload, in my ignorant opinion, could also affect the transaxle/reduction gearbox side and the bearing supporting the drive shaft inside the transaxle and conduct to a reduction gearbox replacement like in this thread:

https://mynissanleaf.com/viewtopic.php?f=30&t=16382

 

[Nubo]

That TSB is interesting in the number and variety of vehicles it covers, and in the strange place that lubricant is added. The work consists of putting grease between 2 surfaces that don't move with respect to each other? When the locknut is torqued the grease will be expelled from the joint, so what's the purpose? And why not lubricate the splines too as long as you are in there? ...

If you make "non-moving" an absolute, it often becomes false. Fretting motion can still occur -- very small movements -- and these can be a source of irritating noises and also wear. An example I encounter from time to time is the chainring bolts on bicycles. These hold chainring to the crank and of course these parts don't move in relation to each other.... But they actually do even though the bolts are all tight as hell. "tick", "tick", "tick".... or "squeak", "squeak", "squeak". The motion must be in the range of microns but the noises are annoying. The fix is to disassemble, clean and LUBRICATE these "non-moving" interfaces and then reassemble and re-torque. The motion still happens but not in such a way as to make an audible sound. And the small amount of lubricant that remains in the interface after torquing also prevents fretting wear which would otherwise make the original problem worse over time.

 

[goldbrick]

I noticed that too in the service bulletin. It seems an odd place to put grease but I'm not an ME so who knows. I am a bike geek though so I'll have to try the chainring bolt thing the next time I'm chasing a BB creak.

I've encounted fretting in my biz but was due to bearingsbeing moved ever so slightly back and forth across the same spots due to vibration while not in transit.

Bottom line, a lot of mechanical things are non-intuitive (to me at least) so if Nissan say this fixes the problem, they may actually be right although I can't understand how it works. My car has a very slight tick when accelerating from a stop but it's not bad enough for me to worry about it. If it gets worse, maybe I'll bring the car in. I'm sure if there was an ICE up there I wouldn't notice it.

 

[nlspace]

..."squeak". The motion must be in the range of microns but the noises are annoying. The fix is to disassemble, clean and LUBRICATE these "non-moving" interfaces and then reassemble and re-torque. The motion still happens but not in such a way as to make an audible sound. And the small amount of lubricant that remains in the interface after torquing also prevents fretting wear which would otherwise make the original problem worse over time.

i agree with you, i'm a lubaholic and i put that s@*$# on everything. That's why i said that the dry-assed splines needs to be lubed too.

If it were the CV joints then it would be noisy all the time and especially when turning. The CVs are a floating joint that doesn't transmit axial loads into the transaxle/gearbox.

Here's an idea for how to get to the bottom of this: put accelerometers on the front strut near the wheel hub and on the gearbox, then drive and record some time histories during periods with and if possible without the subject noise. From there you can extract the power spectral density to identify the frequencies with the most energy making the vibration. Get the bearing dimensions, number of rollers and size, etc and you can calculate the bearing frequencies (race defect on inner or outer race, defective ball/roller pass freq. etc) and compare to rule them in or out. The answer is always revealed by the frequency. Measure the frequency and you can fix the problem.

 

[egl898]

Finally resolved the pulsating vibration after having the car for 3 months. Got an appointment with a local Nissan dealer. I told them I already had the tires rotated and road-force balanced, which did not solve the problem. Also told them that the noise continued when turning left, but not turning right, which indicated to me that it may be a bad right front wheel bearing. Well, at first they checked the left front wheel and said they heard a noisy bearing, so they just replaced it. But that did not solve the vibration. The next day they checked the right front bearing finally, and found it "noisy" too. While replacing the right front bearing, the threads on the right axle were damaged. That meant they had to get a new right front axle. Took almost a week to get a new one. After new axle and right front bearing replaced, the vibration is gone. They thought the bearings were not installed properly at the factory and everything was covered by the Nissan 3-year warranty. I thought I read somewhere if you have a bad wheel bearing on one side, you should always replace the one on the other side too. Have over a thousand miles on the car since purchasing used, and everything else works great. I really like the car, and don't think I'll every switch back to an ICE car.

 

[nlspace]

Right Front Bearing for the win! Glad to hear it is resolved.

Damaged axle thread=> nut torqued too low=> bearing not preloaded properly=> bearing wear and noise.

 

[sony]

Wow, great news egl898. Glad you solved this annoying pulsating vibration.

And the root cause seems to be a wrong torque of the axle locknut as Marko (estomax) said, which damages the wheel bearing and even the threads on the front axle...

Have you an idea on how much would have costed outside the warranty ?

 

[egl898]

Sony, Dealer "list" price on the repairs, including parts and labor, was $491. Fortunately all covered under Nissan warranty.

 

[goldbrick]

$491 seems like a pretty reasonable price for a new axle and wheel bearing with labor. Especially at a dealership. Glad it's fixed.