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Rear Diff Hum

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Posted by: TonyLS

04LSV6

Just would like to know how many other people have had the following problem with their LS, also any advice is appreciated. I'm trying to figure out if it's an inherent problem with the car.

PROBLEM:
At speeds between 50 and 60mph I hear a humming noise from the rear differential. When I take my foot off the gas the humming goes away, it appears again once I hit the gas pedal.

HISTORY:
- When the car was 600 miles old this problem occured. The dealer replaced the entire rear-end instead of repairing the diff since the car was essentially brand new.

- The identical noise started to occur again after about 24,000 miles. The dealer replaced all of the internal differential gears. They told me that these were redesigned gears and that the problem should not come back.

- Now with 29,000 miles the noise is back.

I don't understand this, I've never ever had a vehicle with this problem and I haven't heard of anyone else having a car with this problem. Why can't they get it right? I'm undecided on what to do at this point. The car is still under warranty but I'm concerned when it goes out of warranty what this will end up costing me if it continues again. Do I buy an extended warranty making sure the diff is covered? Do I get rid of it after it goes out of warranty? Do I live with the noise, I have to believe that it will only get worse and worse to the point that it is too loud to ignore. Just venting at this point.

Appreciate feedback.

Posted by: KD00LS

When it happened to me it was the half shafts, it could be the solenoid packing in the tranny or the valve body.

Posted by: beaups

It's the rearend. my 03 has the same issue.

Posted by: TonyLS

Beaups, what have you done about it??

Posted by: ToddG

Its hard to believe the differential is giving you more problems after its been replaced and repaired twice already.

Could it be something else that sounds similar? For example, have you had the wheel bearings checked? My 03 V6 LS had a humming noise coming from the rear and prevalent around 30-50 MPH. A rear wheel bearing was the cause. Evidently, the wheel bearings are known to crap out at about 30K miles, just like mine did. Its worth checking this out because fixing the wheel bearing is a whole lot easier than doing the differential again.

Posted by: TonyLS

Todd,

I believe it's the diff. The reason why is that the noise will go away as soon as I take my foot off the gas. It will appear as soon as I apply preasure to the gas. This is a clasic situation for a diff problem. If it was the wheel bearing then I would hear the noise at all times when the car is rolling.

Thanks for the feed back though.

Posted by: Jim Henderson

Could also be exhaust resonance which is speed dependent and will change with throttle.

Crawl around under your car and check all the exhaust hangers and wiggle and pull anthing under there that might rattle or humm. Tighten whatever you find that is loose.

Good Luck,

Jim Henderson

Posted by: ATLS

When I bought my car around 33,000 miles I picked up on it after driving it for a while, everyone thought I was crazy. A friend of mind told me a quick fix was to turn the radio up. Eventually I took it to the dealership and they replaced the rack and pinion, after that it went away.

Posted by: wayfarers43

Are you sure you're not driving a '99 Mercury Mountaineer. AArg. Hum at 52 mph, goes away when higher speeds. They are known for this.

Seriously, good idea to check exhaust, catalytic converter clamshells have frequent rust (and thus, buzzing) problems at certain speeds.

Also, check with Lincoln directly and also see if this is on any type of recall. Have an independent mechanic drive it to hear what you hear. The dealer mechanics just replace what they get told to sometimes.

Keep pursuing before warranty expires.

Posted by: beaups

I've done nothing. A good way to confirm the general source of the sound is to take a drive with the back seats folded down. It should get MUCH louder. This won't rule out rear wheel bearings or halfshafts but will confirm whether or not the sound is coming from the rearent.

Posted by: TonyLS

beaups,

Have you not had it fixed because it's out of warranty? Has the noise gotten louder over time? How many miles on oyur car and when did it start to occur?

I'm confident that it's the rear diff from my past 2 experiences with this problem.

Thanks for your input

Posted by: mharrison

Mine was/is a passenger rear wheel bearing. It started out only between 40 and 60 MPH. It has gradually gotten worse and now whines all the time. I'll be replacing it within the next 30 days.....

Posted by: beaups

it's out of warranty. my 03 has 80K on it now (I drive a lot). my control arm bushings are all pretty much shot too (rides like crap) which on the LS requires replacing the control arms. $$$ isn't really the problem. SO, my plan is to just put in an entire new IRS when I get around to it, probably about the same time I pick up lowering springs. and it's been doing it for about 20K and hasn't changed much.

Posted by: JoeBman

My 2006 LS v6 had a hum at speeds of 30 to 35. I took it to the dealership and they replaced the ring and pinion gears in the rear end. This was at 6000 miles and has not returned. One of several things to go wrong with this car. Add this to both windshield wiper inserts, fuel filter fuse. trunk out of alignment, transmission slippage and both front doors aligned improperly.

Posted by: TonyLS

JoeB,

how long has the new gear been installed? it sounds like you are displeased with the car, it's justified due to the list of problems you are having. I haven't had major problems other than the rear diff. I love the feel of the car, it drives and handles well, but it's not owning up to the so called "Lincoln Quality".

I just called the dealer now, the service writer is "busy", he's going to call back soon...we'll see.

Posted by: ToddG

Quote:

Originally Posted by JoeBman

My 2006 LS v6 had a hum at speeds of 30 to 35. I took it to the dealership and they replaced the ring and pinion gears in the rear end. This was at 6000 miles and has not returned. One of several things to go wrong with this car. Add this to both windshield wiper inserts, fuel filter fuse. trunk out of alignment, transmission slippage and both front doors aligned improperly.

Huh? There is no such thing as a 2006 LS V6.

And what's a fuel filter fuse? Any relation to muffler bearings?

Posted by: TheRebel

Quote:

Originally Posted by ToddG

Huh? There is no such thing as a 2006 LS V6.

And what's a fuel filter fuse? Any relation to muffler bearings?

Its next to the blinker fluid. Sorry couldn't resist.

Posted by: beaups

hopefully he took it in for the recall on the flux capacitor. 06 v6's were known for failure with that. If it fails while driving at high speed it can cause total loss of rudder control. Anyone ever had rudders fail on their car? VERY scary....

Posted by: JoeBman

It was late at night when the 2006 was typed. I have a 2005 LS v6. The fuse for the fuel door release was replaced. Despite the problems I continue to enjoy this fine car. Enjoy it more than any car before. The witty comments always amuse.

Posted by: beaups