Let start with this: I love my E550. Beautiful car, tons of power, performs wonderfully.

This last Sunday, we decided to take the family on a 14 hour road trip. We left SouthWest Kansas and headed slightly north and east. About 2 hours from, as I was passing someone on a two-lane highway, the car stumbled and threw a check engine light. When we got to Junction City, we popped into Autozone and it basically told us the no. 7 cylinder wasn't firing. So I purchased a coil and we continued to Columbia MO, where we stopped for the night. I got up the next day and in -8* weather, I went to WalMart and bought a tool to replace the coil. Problem solved!

As we were coming through St. Louis, with the cruise set at 70 mph, the car lurched, as if it had downshifted, but the tach indicated otherwise. We continued on our way, spent some time in Richmond, IN and then went to Columbus, IN for a party. When we got off the interstate, and slowed down, the car whirred a bit, much like a noisy toploader transmission in an old Ford and would make a soft clicking sound when accelerating. We made it into down and then as we were slowing to make a turn, the car jumped a couple times, made a horrible grinding sound and then would simply roll, but not move forward under power.

Thankfully, I have a good friend who lives there who has a lift. I had the car towed to his house and we put it up on the lift. I sent the family to the party and we worked to figure out what was wrong with the car. When we got it up in the air, we found that the passenger side axle was broken on both ends. We could grab the axle and spin it (with the car in park) and it wouldn't turn the wheels.

Here's my question. Why would the car refuse to move at this point? I mean, its a 4 matic, and this car is rear biased, correct? Is there something more sinister at play here?

Thanks,
Chris

 

OPEN CENTRAL DIFFERENTIAL.
I keep telling to 4M owners to take a look on CV joint boots each time they can. Boot failure catch in early stage cost $100 to replace, but when not check- ends with long and expensive story like above.

 

You know, in the month of ownership, I simply didn't have time to check the boots. It also leaves nothing on the garage floor and made no noises, so there really weren't any signs of failure until I got to Indiana.

 

Sounds like you bought the car without inspecting it?
Those days everybody has phone camera.
All it take is once a week stick your hand behind front wheels and push the button. Later on you can view the pictures for boot cracks or tears.
The CV joint grease makes HUGE mess on the wheel , inner fender and suspension, so that is not that hard to notice.
Once again, few seconds of preventive checking will eventually save you from horror on the road.
Sound like you missed big party becouse of that?

 

I actually reached under the car and felt around the boots for cracks and tears, though I did not jack it up. Since it was recently serviced and inspected at a local dealer within the last 3 months, I felt it unnecessary to take it to a shop or jack it up in the driveway.

Some time within the time I bought it towards the end of November and January 1st, the inner boot developed a tear and evacuated the grease. The inner boot was not torn but the axle was broken at the outer joint too.

Thankfully, friends picked us up, so my wife and kids were on time to the party and I was only an hour late.

The axle finally arrived yesterday, so my friend will be installing it today. Next, I sort out the logistics of taking another 14 hour drive to get the car.

Chris

Chris

 

Okay.

Axle is installed, but something is whining like crazy upon deceleration. Any thoughts?

Chris

 

What axle did you get? OEM or aftermarket?

There's a lot of parts that can come apart when doing the axle. There's upper and lower ball joints, the brakes, sway bar link, etc.

 

Did you investigate what actually cost both CV joints to break at the same time?
This is the first time I hear about such incident.
Strange thing can happen when axle breaks, but that is weird

 

I was incorrect in my initial assessment. The axle was only broken on the outer end, but the car was in neutral, so when we twisted the axle, we thought it had broken inside the boot. Replaced the axle and now it continues to make the noise it initially did when slowing off the interstate. Its likely the front diff locked and broke the axle at the weakest point. That's our guess anyway.