Dreaded Grinding noise from front of car (sounds central)

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15-02-2018, 07:32 PM
Periphery

Dreaded Grinding noise from front of car (sounds central)
Ok spent a few hours googling Mazda MPS 3 grinding noises and nothing really seems to be similar in symptoms.

One that does sound like my symptoms are from this forum but it is from a Mazda 6 transfer case bearing that spat it (Not applicable to the 3).

So, I'm not sure of its presence at all speeds but its definitely noticeable sub 60km/h
- It has a sound like metal on metal rubbing but on half rotations (180deg)
- noticeable only on deceleration
- Still present when the clutch is in (actually can hear it better as no enine noise)
- I can't distinguish between any side, in fact, it sounds central.
- Have jacked the car and run the car in 2nd gear and cant hear anything (as if its only present when weight on the car)
- When wheels rotated there is no grinding (manually rotated)
- Have rocked the wheels to inspect wheel bearing and there is no slack.
I'm kinda at a loss for ideas, the only thing that is involved in rotations centrally to the car, look like:
- Center drive shaft
- Center drive shaft support bearing
- Clutch
- Flywheels
although last 2 could probably be ruled out by no change when clutch engaged/disengaged

If Anyone has had the same issue or can point me in the right direction I would much appreciate it.

Failing that I need to find a mech I can trust to be honest with me here in Southside Brissy.

Regards.
16-02-2018, 12:29 PM
Byrd

Any grinding in full lock/reverse in full lock? I just replaced the gearbox in my MPS ... it was the diff that shat itself hard.
16-02-2018, 12:44 PM
Periphery

Quote:

Originally Posted by Byrd

Any grinding in full lock/reverse in full lock? I just replaced the gearbox in my MPS ... it was the diff that shat itself hard.

No, no change turning left but it seems to quite down turning right.

Interested in how much you paid for a new gearbox/diff? and how much in labour.

Just draining gearbox/diff oil now to look for broken bits, it looks clean.
16-02-2018, 03:22 PM
Periphery

*RESOLVED*

I can not stress this enough.

REPLACE YOUR GB/DIFF OIL WHEN YOU REPLACE ENGINE OIL!!! (or at least every 12 months).

Issue completely resolved by changing the oil, seems to be the same issue as the "wong Wong" noise others are getting but mine sounded nothing like that.

Put in the recommended (by this forum) Penrite 75/90 GL5/6.

The drained oil did look metallic (like metallic paint flek), there is some wear there but at least know for next time the sound appears.

Phew.....
17-02-2018, 04:12 PM
Byrd

Good to hear - no mine ground hard (same as you, felt it down low/central) mainly on full steering lock, then it'd be great for a week with nothing. It then got worse starting out grinding at low speeds then increasingly worse after 30 mins of driving and turning every corner. Then, it'd be great for a week with nothing then grinding time again. Diff oil was replaced ~ 18 months ago. All this happened right after an engine rebuild ...
21-02-2018, 05:24 AM
Dr. Teeth

Thanks for the timely reminder. I'm sure I'm due for a GB fluid changeover. Will get in contact with Penrite again (it's been a while). Thankfully they're not too far from home.
22-02-2018, 07:19 PM
Periphery

Quote:

Originally Posted by Dr. Teeth

Thanks for the timely reminder. I'm sure I'm due for a GB fluid changeover. Will get in contact with Penrite again (it's been a while). Thankfully they're not too far from home.

My local Supercheap had the penrite in stock, I think years ago these used to be "order in" now seems to be the go-to oil for a lot of LSD performance cars, retails for $59 its steep but worth.
26-02-2018, 05:18 AM
Dr. Teeth

I've got Penrite in my car atm, bought direct from them since they had two different types. Thinking it's almost due for another change.

I'll check SCA (even closer to home) for the stuff.