Diff whine - and Dealer/Mazda response

[IMMX5]

(At the risk of duplicating previous threads!)

We've had our MPS 6 for just over a month now and found the time to go past the local dealer this am to arrange a minor service (10k km service done 17 months ago at ~5k km's - now on ~11k Km's!).

I also wanted to speak to them about the diff whine which comes in at ~80km/h (and disappears if you 'just' engage the handbrake - as has been noted in the forum). Took the dealer technician out and he agrees it's bad enough to be changed. However the service advisor had been doing his homework and had checked with Mazda ("it's normal") so now the Mazda rep needs to check it out. ("Normal" does not mean "right" - it's annoying!)

I'm interested to hear what other MPS 6 owners experience has been with this issue - how many have it, what has dealer / Mazda done etc.?

Slightly off topic:
Also interested to hear if anyone has solved the heavy clutch action / initial resistance of accelerator. Had the misfortune of being stuck in heavy traffic this morning - and it's a real pain having to stop/start frequently. I know Mrs IMMX5 has a problem reversing up our (steepish) drive - frequently stalls. It's be great if one could get better sensitivity out of the throttle - ie. being able to better feather the accelarator on take off.


So it'd be good to hear what success has been had with Mazda / Dealers on these issues.

[kmh001]

My car had the diff whine but I never pursued it with Mazda because I had much worse problems with the resonant vibration, which still remains unresolved. While all that was going on the diff whine eventually went away.

A lot of owners have had their diff replaced only to find the whine comes back. Some are on a third diff. This is probably why Mazda has declared it "normal". It's not right, but it is normal.

If it's any consolation, the whine might just go away like mine did after about 40,000km. Another option if you find the noise unbearable is to install a diff switch to turn the awd and the noise off.

[shinslinger66]

I took mine in for a service and asked them to look at the diff whine and when I came in to picked it up they said that the Tech took it for a drive and he could not hear anything! What a joke...but as I know replacing the diff will not fix the problem I did not pursue it- just never took my car for a service there again.

[shakespeare]

I too have diff whine and resonant vibration, neither of which could be solved, so I perservere and installed a switch to turn off AWD when it annoys me.

I cracked my rear mount on the diff recently and will see how it feels after the new mount has been installed, maybe the whine and vibrations will go away, though in saying the whine is substantially less as the car has more KM's I'm up to 50,000km now and it's not as loud as it used to be?

[shinslinger66]

I have not heard my whine since I got the TBE (loud)- so technically I can say getting the TBE fixed the problem lol

[IMMX5]

Thanks for the feedback so far guys.

Looks like I may have more issues to "look forward to"...

Anyway - I'll be pushing on to some resolution as it's the "major" issue I have (currently) - so will see what transpires...

I must add that so far my 2-year old has very little bothersome otherwise (no known rattles etc.) - and so it shouldn't at only 11200 km's!

I have not heard my whine since I got the TBE (loud)- so technically I can say getting the TBE fixed the problem lol

('Scuse the ignorance but...) Whats a TBE??

[kmh001]

TBE= (from the) turbo back exhaust system.

[lazydog]

What I thought was diff whine, turned out to be a wheel bearing!

Replaced that and now everything seems to be fine!

[Nuliaj]

('Scuse the ignorance but...) Whats a TBE??

Acronyms like TBE which have the ........ underneath them, can be mouse'd over and will give you the meaning.

[shinslinger66]

Acronyms like TBE which have the ........ underneath them, can be mouse'd over and will give you the meaning.

Not seeing that anywhere?

---------- Post added at 07:25 PM ---------- Previous post was at 06:20 PM ----------

BB where did your post go on SRI?

[IMMX5]

Acronyms like TBE which have the ........ underneath them, can be mouse'd over and will give you the meaning.

Thanks - Great stuff - learn something new ATT (all the time!)


(How does that work?)

[blackbetty]

Not seeing that anywhere?

---------- Post added at 07:25 PM ---------- Previous post was at 06:20 PM ----------

BB where did your post go on SRI?

I posted it while still at work (14 hrs today now brain dead) and I couldnt see the underline there so I felt dumb and deleted it

[shinslinger66]

I have never seen the underlines? Tried it in two browsers in case it was Chrome, but still nothing in IE?

Am i on crack???

[kmh001]

I have never seen the underlines? Tried it in two browsers in case it was Chrome, but still nothing in IE?

Am i on crack???

You must be shin lol, I have underlines in Firefox.

[LYNCHY]

i cant see the underlines but can hover over for the meaning weird

[nissanman]

Ok here we go.

Ill join the club.
I took my MPS 6 to Jarrett Mazda today as its under new car warranty and diff whine is getting worse and vibrations also. Got a call at about 10am saying that 3 people have taken the car for a drive and no one can hear or feel what i explain and no one has ever heard of it. So he offered for me to go in that arvo and try and show him what it does by going for a drive. Well, suprise suprise... after 10 minutes it came in with a vengance... i just said " so you cant say thats 'normal' surely?"
he agreed that he thinks there is a problem

He said he was unsure where to start and would ring the state manager of Mazda and ask if its common and what to do. Well 2 hours later he calls me back and says the manager has heard of it and will come up to Jarrett Mazda next friday to drive my car and inspect it. i told him that im happy to go get a RAA (NRMA etc) report done.

Ok heres where the fun is going to be...
He said the State Manager told him to check if it has different sized tyres on the car. well it doesnt... they are all 215/45/18's BUT the holden dealer decided to put new tyres on the front and not replace the rears (which are fine but i think a different brand, therefore different side wall lenghts etc MAYBE)

The Jarrett Mazda manager said that all he can do is get the state mananger to look at the tyres and see what he thinks next Friday.

So.. HELP PLEASE! Who in SA has been to a dealer with this KIND of problem with vibrating and whines etc?????? What dealer was it? Did they replace the Diff etc???

Thanks Guys,

---------- Post added at 05:52 PM ---------- Previous post was at 05:49 PM ----------

EDIT: My 6 has 56,000kms on it. The whine and vibrations get worse the longer you drive it.
ALSO.. I showed the mazda guy how lifting the handbrake up makes it nearly all go away... he tryed it himself and seemed VERY suprised but didnt give a comment.

[kmh001]

The mis-matched tyres could certainly cause the vibration. Just an experiment, you could try matching the tyre height. Do it by inflating the tyres according to a ruler instead of a pressure gauge and measure from the floor to the top of each rim until the heights are all within 1mm.

You'll probably end up with seriously uneven tyre pressures, but it's ok for a short term experiment. Then go for a drive and see how it feels.

[IMMX5]

... measure from the floor to the top of each rim until the heights are all within 1mm.

Alternatively (or additionally) mark the tyre with chalk and roll the car - and thus make sure the rolling circumference is the same.

I don't see that it'd make much of a difference though - more specifically the tyre condition could influence what one hears & feels. Flat spots, tread wear, tyre design, general NVH etc.

Given mine has everything original and only 11000 km it's the perfect example - and totally repeatable (except it seems to not always reappear after one has 'just' lifted the handbrake).


I must admit I started wondering about the security of the rear axle etc after going over a 50km/h speed bump on the way to work today - sounded a bit loose at the back... Wonder if any looseness compounds the problem by perhaps setting up a resonance??? I'll get the car up on ramps tomorrow and have a look!

[nissanman]

I'm on my Iphone at the moment so won't do a large post but my we had some centre diff binding issues on my brothers forestor gt due to different rear tyre sidewall sizes which therefore gave a different rolling circumferance front to rear. We tested it by
marking the tyres at 0degrees... Do some driving test.. Long, short, straight, corners etc and record the differences between left right front rear. Wow some interesting finds. It we are talking mechanical awd there not like the MPS. Cheers guys!

[kmh001]

As we know the MPS awd does not employ a centre differential. So the front to rear rotational variation needs to be accommodated by slipping of the clutches in the diff coupling. But therein lies the problem. The clutches don't slip when they're engaged, but the solenoid engages and disengages them multiple times per second. I don't know the frequency but I'm guessing it's around 10 - 20 hz. So the slippage needs to occur in those micro-second intervals that the clutches are disengaged.

I don't think a few micro-seconds is always long enough to relieve the rotational variation that occurs, so we get vibration due to binding. Sometimes when I turn my rear diff off I can feel a distinct release of pressure from the drive train.

I was able to eliminate the vibration by matching the tyre height as described above. But it wasn't any kind of a solution because the tyre pressures we grossly uneven.

Now here's where it gets interesting. I've had my diff coupling, tail shaft and diff mounts replaced to try and resolve the vibration, without success. However Ottmar and another guy in Germany recently had their gearbox and transfer case replaced and this was the first time the resonant vibration has been successfully resolved.

This finding tends to suggest that on some cars, wear or movement withing the gears or bearings of the transfer case is resulting in the rear wheels being driven at a slightly different rate to the front wheels. The difference may only be minute, but still enough to overcome the diff coupling's ability to compensate.