Rearend humming at 40-45 miles per hour

[Jonesy32]

I thought I had seen a post on this but I couldn't locate in the search options, so I'm sorry if I am double posting.

Anyway, I had my car in for service last week and I mentioned to the service manager that there is a humming (whining) noise coming from the rear differential but only at 40-45 MPH. Well it ends up that they are replacing the entire rear diff on Monday 2/4/08! They took a look and said that there were worn bearings about to go in it and that it was a good thing I mentioned it now before it got any worse. It is completely covered under warranty so no $$$ from me!!

So to anyone out there having this problem and are thinking about not doing anything about it, get it done before it costs lots of ching to get it fixed. I should mention that my only mod is the Mazdaspeed CAI, there is only 7500 miles on it and I have owned it since November 2006.

I will post an update on Tuesday or Wednesday of next week to let you guys know if the sound is completely gone.

 

[shadrag]

It's a common problem, actually more of a quirk. Don't expect it to be gone even with a new diff. Most do it from day 1.

 

[Killer]

what he said. Mine has done it since day one.

 

[leakslikasieve]

mazda knows full well about the "issue". i worked as a service advisor and went to meetings about recalls and everything. the dealer just wants the warranty money. dont complain though

 

[Jonesy32]

Mine has had the sound ever since I bought it also but it has gradually gotten worse. I also noticed when I am on the highway and cruising around 80 MPH, there is a slight grinding noise coming from the diff. Whenever I have a passenger in the car they don't notice it but you know how that goes...I am anal when it comes to sounds that aren't supposed to be there.

Anyway, I am getting it replaced Monday and will update everyone soon after...

 

[MS64MEE]

I had my rear diff replaced a few thousand miles ago for the 45mph whine. When I told them that 1 click of ebrake would make it go away, they took it in right away. Mazda tech told them it was a known nuisance problem but not an issue with the functionality or reliability of the diff. They swapped with a diff shipped from Mazda Tech.

Like I said, its been several thousand miles and the 45mph whine has not come back <knocks on wood>. There is a slight but much quieter whine at 80mph now which also goes away with the 1 click ebrake trick. It's barely noticeable so I'm leaving it as is, for now.

 

[Jonesy32]

update

Okay, I had the diff replaced on Monday with no headaches or problems. They actually finished it in about 4 hours, believe it or not, and they gave me a loaner car to boot. (If you live in western CT, I highly recommend Colonial Mazda in Danbury (hope I don't get in trouble))

The 45mph whine is completely gone now, thank God because it was getting to me. They said that the gears were a little worn and the bearings were starting to go. The grinding I had heard at 80 has vanished but I haven't noticed the slight whine that MS64MEE stated. But then again, I have only drove it about 30 miles since having the new one installed.

Just keeping the peeps updated...

 

[shadrag]

Gone hm? Interesting.

I've been to Colonial Mazda, never had any problems with their service department, but I was only there for an ECU update. The parts guys are pretty helpful too.

 

[leakslikasieve]

I highly recommend Colonial Mazda in Danbury (hope I don't get in trouble))

my mother lives in ridgefield, and she got her cx7 from my old dealer when i worked for mazda on long island. she goes to colonial all the time as she owned a subie from colonial subaru prior. they help her regardless of her not buying from them, as some dealers do down here. also give her a loaner, and dont treat her like an idiot( maybe that has to do with me though, and the fact they know she will slap me on the phone with them in a heartbeat). overall colonial dealerships are pretty good. i would recommend the dealer