Humming sound at air filter box

[AtinLango]

About two weeks ago, i decided to change the front diff fluid. After that i noticed the sound of the engine changed while driving. Also some loss of power.

With close observation, the sound is coming from the air filter box. The mechanic broke one air filter box clip at the time of changing diff fluid. With one having broken before, that makes two broken and only one in place.

I thought the broken clip was causing the humming sound. But even after securing the box with screws, the sound and power loss are still there.

The condition is rather bad now. Some other mechanic is saying it is the turbo that is bad.

Could anyone have any insights on what we can try before going for expensive repairs? I appreciate in advance.

 

[Mike NXP]

Weren't you also having transmission issues causing the vehicle to have no power, what did you find out? Was it a fluid level issue?

As for the humming, you can't diagnose something like that over the internet, especially with no video or audio clips. You'll need to just get under the hood . maybe have someone rev the engine a little bit , and try to listen / feel / poke around to narrow it down. You mentioned that led to the air filter box but it's secure and nothing obvious is loose.

Does it get louder when you rev the motor or does it stay the same?

We don't have many turbo 100 series in the US so not much experience there.

 

[AtinLango]

Thanks for the feedback.

Weren't you also having transmission issues causing the vehicle to have no power, what did you find out? Was it a fluid level issue?

Yes, I had a transmission issue from around Jan to Feb this year - leading to total breakdown of the car. It was resolved by a transmission rebuild. After the rebuild, the car regained full power and was basically running like new for about a week. But I decided that I should replace all diff and transfer fluids to avoid a similar problem. I started with replacing the front diff fluid. During that process, the mechanic also removed the air cleaner box and hoses, and eventually put them back. Things went wrong immediately after that. I started hearing the humming sound and experiencing power loss immediately.

As for the humming, you can't diagnose something like that over the internet, especially with no video or audio clips. You'll need to just get under the hood . maybe have someone rev the engine a little bit , and try to listen / feel / poke around to narrow it down. You mentioned that led to the air filter box but it's secure and nothing obvious is loose.

I will try and share a video at he earliest.

Does it get louder when you rev the motor or does it stay the same?

More or less the same. Maybe just a bit louder when revved.

 

[Mike NXP]

Yes, I had a transmission issue from around Jan to Feb this year - leading to total breakdown of the car. It was resolved by a transmission rebuild. After the rebuild, the car regained full power and was basically running like new for about a week. But I decided that I should replace all diff and transfer fluids to avoid a similar problem. I started with replacing the front diff fluid. During that process, the mechanic also removed the air cleaner box and hoses, and eventually put them back. Things went wrong immediately after that. I started hearing the humming sound and experiencing power loss immediately.


I will try and share a video at he earliest.


More or less the same. Maybe just a bit louder when revved.

Interesting. I wonder why they removed the air cleaner box and hoses to do the front diff fluid exchange. You can drain and fill fluid from below without removing anything up above.


You mentioned the suspect noise doesn't change much with engine revs. If something with the turbo was failing, wouldn't it change noise as the turbo winds up?


It sounds like the problem relates directly to whatever was touched during the front diff fluid service because the noise didn't exist before and it does exist now. Hopefully the front diff has enough fluid in it and everything was put back properly. Otherwise it's just a guessing game on my end.

 

[AtinLango]

Interesting. I wonder why they removed the air cleaner box and hoses to do the front diff fluid exchange. You can drain and fill fluid from below without removing anything up above.

The box was removed for an unrelated reason - in fact mistakenly by one of the mechanics.

It sounds like the problem relates directly to whatever was touched during the front diff fluid service because the noise didn't exist before and it does exist now.

That is my view too, unless it was a coincidence that something went wrong at the same time. In fact I complained immediately that there was queer sound upon starting the car after everything was put back.

Hopefully the front diff has enough fluid in it and everything was put back properly.

Will check again.

 

[Mike NXP]

Trying to follow this vehicle history as it's confusing and your mechanic seems to be not much help......

You had transmission problems, you and the mechanic did a bunch of different things like trying more and less fluid but nothing helped. Eventually the problem was solved by rebuilding the transmission and the truck ran fine right?

Then as preventative maintenance you decided to do the front diff fluid. Once completed, you now have this humming noise....but you also have loss of power again? or are you just trying to solve the humming noise ?

Are you in a remote location, do you have other mechanics? For easy maintenance like diff fluid change, post questions to the forums, we can help you do stuff like that.

 

[AtinLango]

You had transmission problems, you and the mechanic did a bunch of different things like trying more and less fluid but nothing helped. Eventually the problem was solved by rebuilding the transmission and the truck ran fine right?

The transmission issue and resolution is a long story. Along the way I changed to a different mechanic ... eventually transmission problem was resolved. It was just a poor job most of the time.

Then as preventative maintenance you decided to do the front diff fluid. Once complete you now have this humming now but you also have loss of power again?

Well, I have ever had serious power loss before following some repair work. In that incident, the mechanic (yet another mechanic) had left the air intake clamp unsecured. Upon securing, all was very fine. But that was an earlier incident. I have been changing mechanics quite a bit because none of them seems to be able to do the job right the first or second time.