Is any diff noise acceptable?

MarkOliver · Post by **MarkOliver** » Fri 17 Oct, 2008 18:17

Driving the Zed home today I noticed that when lifting off the gas there was a slight whining from the diff. Having driven front wheel drive cars for many years I am not sure what is good or bad, I guess in a Zed you are sat a lot closer to the diff but I don’t have any real appreciation of what if any noise is acceptable from the diff.

The car has done 53k miles, I am thinking that the first port of call is to change the diff oil? Is this a straight forward job? We still have 2 green sevice lights left is it worth wating?

Any comments would be much appreciated....many thanks

AntMan · Post by **AntMan** » Fri 17 Oct, 2008 18:36

I wouldn't normally expect a diff to wine on that mileage are you sure it's the diff and not the wheel bearings ?? I only ask as my mate had nise from the rear which could be heard in drive but clearly when of the throttle from the rear ,he thought it was a diff problem but having checked it it was a pair of rear wheel bearings that had gone.
Having replaced them the rear is silent with no drive noise at all. Have you checked the diff case for signs of a leak?? it should be dry all the way round if it isn't then it may be oil is low causing the issue.
To check the bearings jack the car up and with the hand brake off check for play in the wheels top to bottom left to righ if there is any the bearing is worn just a thought before you look at the diff.

MarkOliver · Post by **MarkOliver** » Fri 17 Oct, 2008 18:39

Thanks for that...its a good idea.

I will check out the wheel bearings. I have made a bit of a beeline for the diff being the source of the noise.

c_w · Post by **c_w** » Fri 17 Oct, 2008 22:42

I think they have some whine to a degree, somtimes it's noticeable sometimes not on the SAME car. Ie sometimes it sounds quiet on the motorway other times you can hear it. Usually it's around 65mph on a light throttle.

I've driven four and they all have some what I would call "normal" diff noise in the background when cruising but it's not alway noticeable to everyone.

Guest · Post by **Guest** » Sat 18 Oct, 2008 08:26

A lot of odd differential-type noises can be generated by worn rear tyres in combination with the road surface.

Yes - an oil change is the first step.

PS - I have moved this tothe correct forum.

phb10186 · Post by **phb10186** » Sat 18 Oct, 2008 12:53

I was under the impression that if it does it at speed it is more of an issue than if it just does it under deceleration.

I think it may just be the cold weather thickening up the oil.... these noises come and go with temperature fluctuations!

maxman · Post by **maxman** » Sat 18 Oct, 2008 20:39

I have a whirring noise from the rear on mine,comes in at about 40mph and stays at the same level even as the speed increases.You cant hear it with the top down.
I have had the car 2 years and it has done 60k ,the noise has not changed in the last 12k.A new diff was £700 when i last checked.

Post by **Robert T** » Sat 18 Oct, 2008 21:16

maxman, I had similar on my zed - turned out to be outer edges of the rear discs rubbing against their guards when they got a bit corroded - nothing to do with the diff at all. I even went as far as having a BMW technician go out in the car with me - he showed me what it was when the car was up on the ramp.

Cheers R.

MarkOliver · Post by **MarkOliver** » Sun 19 Oct, 2008 10:04

Many thanks for all the comments I will check the wheel bearings, change the diff oil, and monitor the noise over the coming months (although its almost trickle charger time).

TitanTim · Post by **TitanTim** » Sun 19 Oct, 2008 10:24

MarkOliver wrote:Many thanks for all the comments I will check the wheel bearings, change the diff oil, and monitor the noise over the coming months (although its almost trickle charger time).

The diff and wheel bearings will feel better if they are used over the Winter months

Tim.

SpunkyM · Post by **SpunkyM** » Wed 22 Oct, 2008 12:34

Diff oil change must be in the top 10 for the easiest things in the world to do.

1) Undo drain plug from bottom of diff and let oil drain out.

2) Put drain plug back in.

3) Undo refill plug (about 4 inches above drain plug)

4) Refill with squidgy bottle and tube until fluid comes out of refill plug.

5) Put refill plug back in.

6) Done.

aj2007 · Post by **aj2007** » Wed 22 Oct, 2008 17:37

Don't forget put the bowl under before 1. else it makes a right mess. Sorry couldn't resist

yangbrucey · Post by **yangbrucey** » Fri 13 Feb, 2009 17:39

I have a 3.0i with 45000 on the clock, and when cruising on the motorway I get a whine when I lift off the accelerator slightly. I hear the noise at lower speeds when lifting off, but it's not as noticable as when at motorway speeds. Having read previous posts on the subject I would say it is definitely coming from the differential and not tyres, discs etc. Will a diff oil change really make any difference? I thought the diff was supposed to be a sealed unit? Any info/advice would be much appreciated. Thanks.

smartypants · Post by **smartypants** » Fri 13 Feb, 2009 19:13

I've got 95k on the clock on my 2.2 - I get diff whine too... always have done (since 18k)

mich · Post by **mich** » Sun 15 Feb, 2009 03:47

If you can change the sound by varying the load then it has to be in the Diff , I would think most make some sort of noise, providing no bits of metal are found in the old oil and not too much backlash is found I would not worry too much unless it gets noticeably worse, what it boil down to is that the mesh setting between the c/w and pinion has changed for some reason or just plain wear on the teeth

Guest · Post by **Guest** » Sun 15 Feb, 2009 16:13

I've had an on/off diff type of whine, which vanished after fiting new rear tyres. As suggested above, a oil change will do no harm, and may even cure the problem.

Diff oil is not changed at any service, so you may as well change it now.

Even if the diff is whining a bit, don't worry about it, as nothing is likely to suddenly go wrong - at the very worst, all which may happen is a bit more noise.

Remember that in a Z3 you are almost sitting on top of the diff anyway, so even the slightest noise will be picked up.

Also you may be hearing noise generated by the lip on the edge of slightly worn discs touching the pads, and changing in sympathy to a tiny amount of movement in the hub bearings between drive and overrun.

NorwegianBlue · Post by **NorwegianBlue** » Sun 15 Feb, 2009 19:54

Careful here...... don't jump to conclusions. I've now had three different Z3's and to a degree they are have a bit of noise coming from that area but after long and careful consideration I came to the conclusion it was the fuel pump.

It's in the same location/direction and does make a high pitched whining noise, that I've found can go after a while. For a long time my ears must have just tuned in to it but after I'd settled my mind it was the pump it just got ignored.

Go have a listen. Are you still sure it's the diff?

c_w · Post by **c_w** » Mon 16 Feb, 2009 14:28

I'm still of the opinion they all "suffer" from diff whine to some degree. The diff design is ancient and the cut angle of the gears is probably the reason they whine by design IMO (some earlier ratio gearsets fitted to this same diff type in the early 80s BMWs had less drivetrain loss but were apparently slightly noisier as result). However it isn't a noise that is VERY noticable, it might just be when your crusing on a light throttle and there's little wind noise etc.

yangbrucey · Post by **yangbrucey** » Mon 16 Feb, 2009 19:34

Pretty sure it's the diff as the noise definitely comes and goes with just slight lift off and on of the accelerator.
Bizzarely enough, I took my hardtop off today to get it painted and I couldn't hear the noise when driving home! Now I know there's a wee bit more wind noise when the soft top's up, but the whine was really quite pronounced. I'll give it another listen on the way to work tomorrow.

c_w · Post by **c_w** » Mon 16 Feb, 2009 21:25

yangbrucey wrote:Pretty sure it's the diff as the noise definitely comes and goes with just slight lift off and on of the accelerator.
Bizzarely enough, I took my hardtop off today to get it painted and I couldn't hear the noise when driving home! Now I know there's a wee bit more wind noise when the soft top's up, but the whine was really quite pronounced. I'll give it another listen on the way to work tomorrow.

Yep that sounds about right, the noise will be more noticeable with the hardtop on as it's quieter all round so the next noise becomes more apparent.

smartypants · Post by **smartypants** » Mon 16 Feb, 2009 22:42

My diff noise is much more prominent with the roof up too

yangbrucey · Post by **yangbrucey** » Tue 17 Feb, 2009 11:39

Could only just hear the whine on the way to work today, and that was only if I listened really carefully. The frequency must be drowned out by the wind noise. Also noticed a lot more vibration through the car when travelling at motorway speeds without the hardtop. Hardtop must stiffen the ride up. Is this normal? Is there anything that can be done to reduce vibration and scuttle shake when not using the hardtop?

c_w · Post by **c_w** » Tue 17 Feb, 2009 13:36

yangbrucey wrote:Could only just hear the whine on the way to work today, and that was only if I listened really carefully. The frequency must be drowned out by the wind noise. Also noticed a lot more vibration through the car when travelling at motorway speeds without the hardtop. Hardtop must stiffen the ride up. Is this normal? Is there anything that can be done to reduce vibration and scuttle shake when not using the hardtop?

Nope not really. A front and rear strut brace plus the body brace may help but it's not really fastening onto the parts that really need it (the top of the winscreen to the rear scuttle). Also make sure your wheel balance is spot on as they are very sensitive to out of balance wheels on both front and rear and will send a shudder through the car.

yangbrucey · Post by **yangbrucey** » Tue 17 Feb, 2009 15:24

Thanks c_w. I was thinking of checking the wheel balance, so I'll get that done at the weekend.
I've seen some photos of Z3's with a brace running over the top of the engine compartment from one wheel arch to the other - is that a body brace?

Guest · Post by **Guest** » Tue 17 Feb, 2009 15:49

No - that is a strut brace. The Body Brace runs from each side of the 'X' brace below the engine to join on to the Butt Strut.

On the picture below, the Butt Strut can be seen passing below the front silencer, and the two Body Brace runners are bolted to it, passing forwards to the 'X' brace.

Strut braces do a little, but are nowhere near as effective as these bits.

yangbrucey · Post by **yangbrucey** » Tue 17 Feb, 2009 20:17

Thanks for explaining that Mike. I take it you're talking about a fair whack of money to get a Butt Strut and Body Braces fitted?

Post by **Robert T** » Tue 17 Feb, 2009 20:21

yangbrucey wrote:Thanks for explaining that Mike. I take it you're talking about a fair whack of money to get a Butt Strut and Body Braces fitted?

Yeah, spanners are getting terribly expensive these days - cost me £20 for a set the other day.

Don't there is much problem fitting these yourself, other than my usual one of not having some way of getting under the car.

Cheers R.

Guest · Post by **Guest** » Wed 18 Feb, 2009 09:48

They are about £200 each, which is pretty good value - buy them directly from Strong Strut via their website, as the UK dealer, CA Automotive, charge a good bit more.

They do a really good strut brace too, in steel, for about £200 also.

Delivery from Arizona is usually a matter of days.

yangbrucey · Post by **yangbrucey** » Wed 18 Feb, 2009 20:32

Thanks for the info Mike. I'll get the wheels balanced first and then take it from there.

c_w · Post by **c_w** » Thu 19 Feb, 2009 14:05

Robert T wrote:
yangbrucey wrote:Thanks for explaining that Mike. I take it you're talking about a fair whack of money to get a Butt Strut and Body Braces fitted?
Yeah, spanners are getting terribly expensive these days - cost me £20 for a set the other day.

Don't there is much problem fitting these yourself, other than my usual one of not having some way of getting under the car.

Cheers R.

Trolley jacks are terribly expensive these days

yangbrucey · Post by **yangbrucey** » Sun 22 Feb, 2009 20:58

Got my wheels balanced on Friday. What a difference! I was getting a lot of shudder through the whole car at motorway speeds, but after the wheel balancing, there was none. They weren't out by much, so it just shows how sensitive the Z3 is to poor wheel balance. I got the wheel alignment checked too and it was spot on.

Had a bit of a nightmare at the tyre fitter's though. Got the wheels balanced at Farmer's Autocare in Edinburgh. When I turned up the manager came out to look at the car and said I needed the tyre valves changed on the rear wheels too as they were the wrong size. I sat and had a cup of tea and had the occasional look over at how the boys were doing with my wheels. To my utter disbelief I watched one of the laddies take a 4 pound metal hammer to one of the wheels to knock the valve out. I could hear metal on metal contact from across the workshop! I thought I must be seeing things, but it went on for about 2 minutes. When the wheels were finished, the manager checked the wheel alignment then brought the car over. The near side rear wheel rim was dented and chipped badly around the tyre valve - I was almost speechless with rage (I got all 4 wheels painted about 3 months ago and they were immaculate). I didn't realise it was my responsibility to tell the tyre fitters that my wheels had just been painted and not to give them a good rattling with a 4 pound hammer! Anyway, when I pointed the damage out to the manager, he arranged to get the guys who originally painted my wheels to come out and repaint the damaged wheel. There was also no charge for the work they carried out.
I had a similar experience with another car 3 years ago. I'd just had alloys painted and got the rear tyres replaced at Kwik Fit. When I got home I noticed there whas a chip on the rim on each wheel where they'd used a crowbar to wedge the tyre off. So the moral of the story is, when you go to a tyre fitter, point out that your wheels are immaculate before they start any work, then give them a thorough inspection before you pay the bill.

mich · Post by **mich** » Mon 23 Feb, 2009 00:47

You must be short of good mechanics over there, did the idiot still keep his job

c_w · Post by **c_w** » Mon 23 Feb, 2009 09:34

Sounds bizarre although I am very particular who changes tyres on my car and I only use someone I know. You genereally just cut the valve out from inside the rim with a sharp knife.

There is no need to ever mark an alloy wheel if the machine is used properly. The initial levering off of the tyre should be used against a rubber protector then the machine takes the rest off.

zroadster.net

Is any diff noise acceptable?

Is any diff noise acceptable?

Diff Noise

Diff Noise

Body Brace

Body Brace