Noisy diff??

[captainbizzaro]

Evening all,

Went for a spank tonight and due to the fact I have no stereo and just the music of the 12A it means I hear every single bump and rattle. I\'m sure we can all relate to the paranoia that sets in and I\'m sure my diff is getting noisy as I sometimes get a rumble from the back end. This isn\'t the tyres as it happens on any surface and at any level of driving enthusiasm-it\'s not constant but comes and goes.

So....two questions...

1. For those of you that have encountered a noisy diff doe\'s mine sound like it\'s having a crisis?

2. And if it is- will changing the oil in the axle for a particular kind increase the longevity of my diff so it will at least get me to rotorstock and back without throwing a strop.

Any other suggestions as to what it might be are welcome-it isn\'t loud and if I had a stereo I would hear it but I know it\'s there so it bugs me!

Cheers

[myatt1972]

Are you sure its not a wheel bearing?
Ive had noisey boxes before but not diffs.
Keith...

[captainbizzaro]

I did wonder about it being a wheel bearing too to be fair Keith-the only reason I thought it wouldn\'t be is because it\'s just gone through an MOT and presumed it\'d have some play in it if it was that noisy. Maybe it is a bearing and is grumbling because it\'s having to work for a living for once!

[David Nock (RIP)]

Some years back I changed one of the rear wheel bearings after the MOT man noticed a bit of \'rock\' when checking the offside rear and gave me an advisory. The bearing that came out was perfect as far as I could tell. The \'rock\' got slightly more noticeable over the next couple of years, then a distinct \'clonking\' was coming out of the diff on the overrun.

I swopped out the diff for a spare and all cured.....the side bearing in the diff (the one that carries the splined end of the half shaft) had noticable play in it. When you rocked the offside back wheel the play transmitted itself right along to the wheel, like down a 3\' shaft; so rocking the wheels was actually wobbling the end of the half shaft at the diff bearing.

When I did the swop out I used some full synthetic gear oil (Castrol, Valvoline- also others do it). It made for a smoother ride somehow.

Well worth checking/changing the axle oil Tim....my experience was that it ain\'t always the wheel bearings.

Also diffs are like creaking gates....they make noises for years but don\'t tend to dramatically break.

[Mir]

Hi I have recently installled super q Kazz 1.5 in my car. I am hearing some nasty noises from the diff when I do sharp turnings..I did not put the Kazz oil rather i put Gl5 80W 90 because I thought I would run it on that first and then Install Kazz Oil in it...so the senario is the same dont know what is creating this noise...and whether changing of the oil would address this issue for me....

[David Nock (RIP)]

Is it an FD Mir? I don\'t know anything at all about them but if you\'ve put the correct grade of Gear Oil in I can\'t see that another change will help it much?

Has it got exposed drive joints at the back? Is one failing?

[captainbizzaro]

Cheers Dave, I don\'t get any knocking on over-run or when taking up drive so will just treat it to an oil change and see what happens.

[mpk490p]

all my RX7\'s have had a noisey diff at some point, they will keep going so i shouldnt worry to much but its worth thinking about getting another one rebuilt they you can just swap them over