lvmilkman1

Hello all I have an 09 E350 Sport rear wheel drive. I have been getting a low wow wow wow sound out of the rear end of the car but it has been elusive! This is only audible until about 20mph and then it disappears.


I have done the following:

• Replaced bearings on both sides
• Replaced both spindle/hubs on both sides
• replaced both rotors and also had the new rotors turned (non factory drilled rotors) to make sure that they were true
• Changed differential fluid
• changed CV axle on passenger side
• New tires Continental Extreme Contact DWS

Still I have a wow wow wow.....I'm losing it. The CV axle boots were not damaged in any way.


The last two things I can think of are either the drive shaft from tranny to the differential and also the differential gears/bearings.


Does anybody else have any suggestions?


BTW, I took pictures of the bearing replacement and will do a write up....the ***** of that job is if the emergency/parking brake "self adjusts" you are screwed and you have to remove the entire mechanism which is in the center of the vehicle and above the drive shaft....no access from the top....you have to "reset it" and then zip tie it together so it doesn't retention, connect everything then snip the zip tie.

noka

Not much else left besides drive shaft. But hey, as long as you're having fun!

lvmilkman1

It's killing me....I would have bet the ranch it was the outer bearing....nope.

KEY08

Not much left. Differential I would guess. How many miles?

mleskovar

How did the tires that were removed wear? Any cups or uneven wear? How about all the suspensions arms/links and mounting points and rubber? It sounds like something is fighting movement and once up to speed settles in. Give everything a good shake and twist by just lifting the tire free of the ground and using it for leverage.

lvmilkman1

The vehicle has 64k miles on it and has been immaculately maintained. All of the suspension components are really tight.


The tires had very light cupping and had 20k miles on them. They were unidirectional tires.


This really has me scratching my head.


I think next is the Rubber Flex joint on the drive shaft in the rear and then if nothing is found there, then in to the rear differential itself.


Thanks for all of your input and any more would be great as well.

mleskovar

Cupping on rear tires is rare and indicate something wrong with alignment. The wow-wow sound is usually associated with front tires and is often caused by failed strut bushings.

lvmilkman1

Thank you for the feedback Mleskovar I will check that out and get a four wheel alignment. I really appreciate the suggestion.

KEY08

Have the new tires been rotated yet? In other words, did the cupping happen when they were on the front? Cupping in the rear is definitely not normally found.

lvmilkman1

The tires are staggered as it is a Sport version so they can't be rotated. It also has the handling package.