Trying to ID Drivetrain Sound

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DainBramaged
Posts: 15
Joined: Tue Feb 16, 2010 5:46 pm

Trying to ID Drivetrain Sound

Postby DainBramaged » Tue Aug 17, 2021 9:22 am

Hi Folks:

My Pathy is currently @ 195,121.

Over the past two weeks, I have begun hearing a "spooling-up" sound, for lack of a better term. As my speed increases, the sound grows higher in pitch. As I decelerate, it slowly lowers in pitch. It is not correlated with engine RPMs. With my limited knowledge, the would seem to limit it to transmission, drive shaft, and related items and indicates it is not the engine. I have had work done previously on the drive shaft. Possibly something there? Maybe a bearing?

Any thoughts/ideas would be greatly appreciate!

Thanks,

Andrew


TooMuchControl
Posts: 335
Joined: Tue Apr 28, 2020 4:41 pm

Re: Trying to ID Drivetrain Sound

Postby TooMuchControl » Thu Aug 19, 2021 3:31 pm

With the windows up.
When you start, do you hear a whirring sound inside the cab?

Is the noise similar to let's say the pitch / frequency of radio noise? It goes up with engine RPM and then dies down a bit on the start of the car?

When you place the car in gear, with the brake on, do you hear the pitch (in the background) a bit? Something as if the frequency is "above" the engine running?

Or is this something you hear explicitly when moving, in gear, at certain speed.

DainBramaged
Posts: 15
Joined: Tue Feb 16, 2010 5:46 pm

Re: Trying to ID Drivetrain Sound

Postby DainBramaged » Fri Aug 20, 2021 2:27 pm

TooMuchControl wrote:
Thu Aug 19, 2021 3:31 pm
With the windows up.
When you start, do you hear a whirring sound inside the cab?
No, I do not.
Is the noise similar to let's say the pitch / frequency of radio noise? It goes up with engine RPM and then dies down a bit on the start of the car?
It does not sound like radio noise. I would compare it more to an engine on a jetliner gradually spooling up. It does not go up with RPMs.
When you place the car in gear, with the brake on, do you hear the pitch (in the background) a bit? Something as if the frequency is "above" the engine running?
Not at all.
Or is this something you hear explicitly when moving, in gear, at certain speed.
Yes, the faster the car is moving, the higher the pitch of the noise. If you were to put the car in neutral and turn off the car, the noise would still be there.

CRC11007
Posts: 32
Joined: Sat Nov 17, 2018 5:14 am
Location: Monument, CO

Re: Trying to ID Drivetrain Sound

Postby CRC11007 » Sat Aug 21, 2021 4:22 pm

I’m guessing wheel bearings. While you’re in there, I would replace the CV joints, front seals, and u-joints on the driveshafts. With your high mileage, these are worth replacing anyway.

TooMuchControl
Posts: 335
Joined: Tue Apr 28, 2020 4:41 pm

Re: Trying to ID Drivetrain Sound

Postby TooMuchControl » Sat Aug 21, 2021 6:55 pm

Any issues with the transmission?

Your last comment states that if you turn the truck off, the noise would still be there (can't be right...right?)

If it's the driveshaft - simply remove it. Mark the positions on both ends. If it's isolated, then you have the answer. For me, I would remove the shaft and take a ride.


For me there's simply too much going on under the hood to determine noises and hums, I feel.
There are a few simple tests that can be performed to check those items from outside the car, with a helper.

Wheel bearings can be checked by rotating the wheels off the ground and holding the strut spring. It will feel like you are turning a pepper grinder. Just close you eyes, hold the spring, and rotate the wheel. It's surprising effective test.

Idler pulley and tensioner would be items that I would suspect, but you state that it's not relative to engine RPMs, which eliminates those for me. Those would certainly pitch up and down with engine RPMS and are known to fail, and are easily tested.

If you suspect Tx, and haven't performed an Tx oil change, it might be a good idea to have the condition of the oil checked out. More of a PM thing.

DainBramaged
Posts: 15
Joined: Tue Feb 16, 2010 5:46 pm

Re: Trying to ID Drivetrain Sound

Postby DainBramaged » Mon Aug 23, 2021 7:59 am

TooMuchControl wrote:
Sat Aug 21, 2021 6:55 pm
Any issues with the transmission?
Nothing obvious? It seems to shift smoothly. Midas told me it was slipping during my routine oil change. But I've never felt it slip? I don't really trust Midas much more than oil changes...
Your last comment states that if you turn the truck off, the noise would still be there (can't be right...right?)
My fault...I didn't clarify. The other day, I was driving at 55mph. I put the truck in neutral and turned off the ignition. Even moving at 55mph, I could still hear the noise.
If it's the driveshaft - simply remove it. Mark the positions on both ends. If it's isolated, then you have the answer. For me, I would remove the shaft and take a ride.
This is exactly the isolating I was looking for. Yet, I didn't even think about turning the Pathfinder into a FWD...LOL! Thanks for advice. I'll try this.
Wheel bearings can be checked by rotating the wheels off the ground and holding the strut spring. It will feel like you are turning a pepper grinder. Just close you eyes, hold the spring, and rotate the wheel. It's surprising effective test.
I'll definitely try this, too.
Idler pulley and tensioner would be items that I would suspect, but you state that it's not relative to engine RPMs, which eliminates those for me. Those would certainly pitch up and down with engine RPMS and are known to fail, and are easily tested.
Yeah, I think I can scratch these off the list.

Thank you for the suggestions. I appreciate them!

Andrew

TooMuchControl
Posts: 335
Joined: Tue Apr 28, 2020 4:41 pm

Re: Trying to ID Drivetrain Sound

Postby TooMuchControl » Mon Aug 23, 2021 2:54 pm

As for the driveshaft..maybe not the best idea....i'm positive it won't work out...
For whatever reason I thought you had performed service on the front shaft, not the rear....

Sorry on that..argh.

Hope you have some luck!

DainBramaged
Posts: 15
Joined: Tue Feb 16, 2010 5:46 pm

Re: Trying to ID Drivetrain Sound

Postby DainBramaged » Fri Sep 03, 2021 10:12 am

TooMuchControl wrote:
Mon Aug 23, 2021 2:54 pm
As for the driveshaft..maybe not the best idea....i'm positive it won't work out...
For whatever reason I thought you had performed service on the front shaft, not the rear....

Sorry on that..argh.

Hope you have some luck!
Well, my worrying was all for naught. I performed your pepper-grinder test. That was effective at showing that the right bearing was bad. I replaced it, and all of the evil noises disappeared. I have not heard a wheel bearing sound like that before; however, it's it's all done. It set me back $125; SO much cheaper than I ever dreamed of.

Thank you much for the help!!

Andrew

TooMuchControl
Posts: 335
Joined: Tue Apr 28, 2020 4:41 pm

Re: Trying to ID Drivetrain Sound

Postby TooMuchControl » Fri Sep 03, 2021 5:09 pm

That's awesome! I'm glad it had worked out.


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