Some advice needed.

[aelevy81]

Last night I was taking a trip to visit my family for a birthday this weekend. unfortunately I had to turn around because of something strange that happened while driving.

So while we were driving we would feel this horrendous vibration when decelerating. This only occurred when I would let my foot off the gas and would coast. It does occur when braking as well.

As soon as I found a place to pull over and stop, I noticed a burning smell coming from the rear passenger side tire. The tire itself looked fine, no hole, no bubbles or wear on it.

I was able to drive it back home around 60 miles or so at 60mph with the cruise control set. No noise when accelerating.

Any opinions would be most helpful I'm not very tech/car savvy.

 

[thebrakeman]

-Check the lug nuts for proper torque.

Take it out again until you get the noise. Get out and compare everything right-to-left:
-Tire temperature (by feel)
-Rotor temperature (by feel...BE CAREFUL...Can be VERY hot. Touch quickly then pull away. Just get an idea if the right is significantly hotter than the left)
-Wheel/hub itself warmer at the center (by feel)?

Jack up the rear, both sides:
-Try to wiggle the tire/wheel, side to side, and top to bottom. Compare to the left side. Same behavior?
-Rotate each tire (not swapping them, physically spin them). Same behavior?

If no clues based on heat differences and basic behavior, you'll need take off the wheel, and start looking at things. Or take it to a shop. If you take it to a shop, be sure you can duplicate the problem.

 

[Explorer_PL]

Grease from the axle boot splashed on the rotor ?

 

[aelevy81]

[MENTION=74489]Explorer_PL[/MENTION] there is some black splatter I noticed behind the car. Similar to little black dots, powdery substance marking the back latch of the explorer.

 

[Explorer_PL]

I would jack it up, choke the front wheels, make it secure, crawl under the rear axle, with tranny in Neutral try to spin the tires, they should spin in opposite direction. Listen to any noise. Maybe your half shaft is bad, or maybe you have some differential issues. Check brake lines for any leaks. Be careful when you are under.

Maybe you drove over something on the road ?

 

[aelevy81]

[MENTION=74489]Explorer_PL[/MENTION]

As I said in first post, I'm not car savvy. I don't know anything about cars. So i'm bringing it to the mechanic in the morning

Side note and observation, when putting the vehicle in reverse my wife said that she noticed the noise and the muffler was shaking as well. After I put it in park, i touched the muffler and it seemed loose.

 

[aelevy81]

Turns out the differential needs replacement

 

[aelevy81]

What would cause the differential on this explorer to go bad??

 

[Explorer_PL]

Strange. How many miles ?
If it was serviced before maybe wrong oil was used ?
It requires some heavy gear oil.

I change fluids in differentials every 60k, I am at 204 K and no problems so far.

 

[aelevy81]

[MENTION=74489]Explorer_PL[/MENTION]

Only 70,000 miles.

Mobil Super™ High Mileage 5W-30 oil

As far as fluids for differential, I'm really not certain, I've only gotten basic oil change and servicing done on it. So I would have to guess that it is because of lack of respect from myself towards my vehicle and thinking that it was enough..