2011 lacrosse has humming coming from the rear

[cpnichols63]

I have a 2011 Buick Lacrosse and there is a low pitch hum coming from the rear/trunk area when I'm driving. It speeds up when I go faster and slows down when I go slower. Had the tires checked, nothing there. Any ideas?

 

[92sub]

items that come to mind:
Rear wheel bearing(s)
Rear differential if AWD
Tires (what does 'checked' mean?)
Fuel Pump (not as likely)

I don't recall anyone on the forum complaining of a similar concern so you might be on your own here.

 

[HiHoSilver]

My 2012 makes the same humming noise. I haven't had the dealer look at it yet. The noise isn't there all of the time, so I think that is going to be an issue for the dealer to replicate. But when the noise is there, it gets louder and softer depending on how I accelerate. I don't think it is the tires. It almost sounds like something electric to me. My first thought was fuel pump or maybe some sort of interference coming through the rear speakers. I will mention it to my dealer at my next oil change and see what they say.

 

[92sub]

My 2012 sounds like something electric to me.

If you have eAssist it's probably the fan in the trunk used to cool the batteries.

 

[HiHoSilver]

If you have eAssist it's probably the fan in the trunk used to cool the batteries.

No eAssist. I have the 3.6.

 

[mylacrosse]

I am wondering if it maybe the wheel bearings?

 

[mmadden2]

Old electrical joke...

Why does a transformer hum?
Cause it doesn't know the words.

So... what's the dealer have to say about this?

 

[Richard1869]

I have had the same problem with my 2002 Explorer (not my 2012 Lacrosse) for many years. I took it to my Ford dealer several times to have them look at it and their answer was “differential harmonics”. I was told to live with it or replace the entire rear end. I eventually took it to a local shop and the mechanic added heaver weight oil and a can of differential conditioner and the hum is 90% better now, not gone completely but almost.

 

[Schoenerman21]

I have the same exact issue. I've eliminated the tires (inflated and deflated them), the transmission (same hum in any gear), the engine (same hum regardless of RPM). The hum is CAR SPEED DEPENDENT whether in gear or neutral. I'm convinced it's in the differential. I heard that heavy weight gear lube would help.......or I could live with it....BUT, can it hurt the differential with heat build-up?????

 

[Schoenerman21]

I have the same problem. It is NOT the engine, transmission, tires or exhaust (I've done speed tests, put the car in neutral, changed the tire pressure, etc.) I do believe it is the differential. One person suggested changing the differential lube or using a premium 90W lube. It solved the problem. I believe this is the most viable solution. ONE QUESTION...if it is the differential lubrication, am I damaging the differential by driving it. Summer is coming and it seems the hum is friction and it could over heat. ANYONE??

 

[GMLover]

My 2010 Lacrosse also had a humming noise at approx. 30,000 miles. Dealer put in new right front wheel bearings.

 

[G-64300]

Its ur rear coupling oil pump. Tryst me lol

 

[Rscoops]

Its ur rear coupling oil pump. Tryst me lol

Why you lol ? Is this a serious response or what ? I have a hum that started last week, 93k miles on 2011 Lacrosse.

 

[Frustrated in Cincinnati.]

Why you lol ? Is this a serious response or what ? I have a hum that started last week, 93k miles on 2011 Lacrosse.

We are having the same humming issue! Put new wheel bearings on......no change, sound still there! My husband did spot a broken coil spring. We are replacing those this weekend. Fingers crossed this is the issue! Ous is a 2013 Buick Lacrosse with 90,000 miles.

 

[PulpFriction]

Had hum in the rear and sensor code. Independent garage diagnosed both rear hubs bad and replaced. Instant quiet. For a few months. Now a bit of noise again. We’ll see. Bearing these days are garbage. Don’t know what the best brand is.

 

[Chef]

I have a 2011 Buick Lacrosse and there is a low pitch hum coming from the rear/trunk area when I'm driving. It speeds up when I go faster and slows down when I go slower. Had the tires checked, nothing there. Any ideas?

I had the same sound on my 13 lacrosse
I rotated back tires to front and it stopped