Humming Noise At Rear of Vehicle

[SUV_RIDER]

Hello, i've a 2003 Ford Explorer (V6) with 68K miles. I am hearing some type of humming noise at the rear of vehicle while traveling a low speed (i.e. 30 miles per hour or so). It's like when i let off the gas pedal, the noise fades away but when i accelerate again, the noise re-appears. Could this be coming from a defective hub bearing assembly or what? If so, how do i determine which side of vehicle the noise is coming from? Has anyone else experience this problem with your Explorer? Thanks

Note! I replaced both front hub bearing assemblies but the noise was a roaring type noise (like woom woom woom woom)) when i replace the front ones, i was hearing the noise while turning in a deep curve to the right and or left. The noise on the rear is like a whistling noise.

 

[alexk]

I think I have the same thing at 30-40 mph. My solution, turn the radio up.

 

[SUV_RIDER]

That's exactly what i've been doing but i would like to know where the noise is coming from. Thanks

I think I have the same thing at 30-40 mph. My solution, turn the radio up.

 

[XCAMP]

Check your differential fluid level. If it's low, it will cause the noise. If that's it, then find out why it's low which could be a bad seal.

 

[OMEGA4X4]

I have a low, deep, bass like, droning noise... like HMMMMMMMMMM between 65-75..

 

[XCAMP]

Does the noise go away when you let off the gas?

 

[SUV_RIDER]

Thanks, i will as soon as i figure out how to. Never done that before!

 

[SUV_RIDER]

Mine does, every time!

 

[XCAMP]

If it stops when you let off the gas, it's most likely low oil level, bad oil, or your seal and bearings need to be replaced according to the related TSB (search for it on this board).

To check the oil you simply open the fill cap and stick your finger in (not when it's hot). The level should be right below the fill hole. If it's low add some correct grade oil/modifier and see if the noise goes away. While you are there, look for a leak where the shaft meets the case.

 

[SUV_RIDER]

Alright, i will give it a try when time allow and it warms up. It's cold as heck in the Louisville, KY area right now. What tool do i need to remove the fill cap? How do i determine what type of oil I need? Would this be in my owner's manual? This will definitely be a learning experience for me for the only fluids i have ever changed are oil/anti-freeze/brake fluid. i appreciate your help! Thanks alot!

If it stops when you let off the gas, it's most likely low oil level, bad oil, or your seal and bearings need to be replaced according to the related TSB (search for it on this board).

To check the oil you simply open the fill cap and stick your finger in (not when it's hot). The level should be right below the fill hole. If it's low add some correct grade oil/modifier and see if the noise goes away. While you are there, look for a leak where the shaft meets the case.

 

[SUV_RIDER]

One other question, how much oil should i put in the differential if i decide to just change it? Do you know if the local oil change shops do this type of work and is it expensive? And or is it very easy to do at home yourself?

If it stops when you let off the gas, it's most likely low oil level, bad oil, or your seal and bearings need to be replaced according to the related TSB (search for it on this board).

To check the oil you simply open the fill cap and stick your finger in (not when it's hot). The level should be right below the fill hole. If it's low add some correct grade oil/modifier and see if the noise goes away. While you are there, look for a leak where the shaft meets the case.

 

[XCAMP]

You might want to grab a haynes manual from the auto parts store, they are only like $20 and explain the procedure in detail. Look under the explorer from the back and you will see two plug holes on the differential, the top is the fill hole, put a wrench on it and open it, some fluid might just come out when you open it. If you need to replace the fluid, you might want to just take it to a shop and get it flushed. Make sure they put in 75w-140 oil with modifier if you have LSD.

 

[SUV_RIDER]

Alright, will do! I called Valvoline Instant Oil Change to see if they change the oil in a differential. They do and charge a fee of $59.99. The Haynes manual states that the differential holds approximately 1.75 qts. The oil shop told me 5 qts. What is a "LSD?" I have a 2003 Eddie Bauer 4x4 with a V6 @ 68K miles.
thanks again for the assistance!

You might want to grab a haynes manual from the auto parts store, they are only like $20 and explain the procedure in detail. Look under the explorer from the back and you will see two plug holes on the differential, the top is the fill hole, put a wrench on it and open it, some fluid might just come out when you open it. If you need to replace the fluid, you might want to just take it to a shop and get it flushed. Make sure they put in 75w-140 oil with modifier if you have LSD.

 

[XCAMP]

Considering a regular oil change is like $30, that doesn't sound that bad. Not sure how many qrts it takes off hand. LSD = Limited Slip differential

 

[SUV_RIDER]

Humming at Rear of Vehicle

Alright, thanks again for the assistance.

Considering a regular oil change is like $30, that doesn't sound that bad. Not sure how many qrts it takes off hand. LSD = Limited Slip differential

 

[XCAMP]

Takes about 1.5 qts and about half a bottle of modifier.

 

[SUV_RIDER]

So how do i determine if i have "advanced trac" or not?

Also, if you have advanced trac on yours, it makes the differential oil change a little more difficult because you have to fill it up through a third fill plug related to the ABS.

 

[XCAMP]

Not sure, but mine says advanced trac on the back lift gate.

 

[SUV_RIDER]

Mine don't! i will check the owner's manual and or visit the local FORD dealer to find out which type i have. Thanks

Not sure, but mine says advanced trac on the back lift gate.

 

[jrford]

Another tip, I found if i show up at the quick lube joint, with my own fluid, Mobil1, they only charge me $15 to siphon it out and refill with my stuff, $30 for both. If you have two do both and fill with Full Synth 75-140w F/R . I use Mobil1 also amsoil or royal purple are good too. They say in the book to use 80/90w for the fronts but a couple of rebuilders said the factory only does that to save money, and when they rebuild them they put in the 75w-140. If you have LSD there is a special bottle (friction modifier) that needs to be added.