Slight increase in diff noise
Discussion
Hi folks...
I have noticed recently that my diff is making slightly more noise than it used to. It's not making a horrendous noise; it's more like a "singing" sound. And it's not horrendously loud either - really only noticeable on the rare occasions when I've got the roof on, and mostly between 20 to 40 mph. It sounds perfectly "normal" diff noise, but it's just got slightly louder in recent weeks. The car has covered about 72,000 miles.
How concerned should I be about this? Is it likely the diff is slightly low on oil, and how easy is it to top up?
Will I be causing excessive wear or damage by driving it?
The car will be due a service in January/February. Should I do something about it before then, or not worry?
I have noticed recently that my diff is making slightly more noise than it used to. It's not making a horrendous noise; it's more like a "singing" sound. And it's not horrendously loud either - really only noticeable on the rare occasions when I've got the roof on, and mostly between 20 to 40 mph. It sounds perfectly "normal" diff noise, but it's just got slightly louder in recent weeks. The car has covered about 72,000 miles.
How concerned should I be about this? Is it likely the diff is slightly low on oil, and how easy is it to top up?
Will I be causing excessive wear or damage by driving it?
The car will be due a service in January/February. Should I do something about it before then, or not worry?
but if its low already the damage is done and either you or your garage need flogging 
I've just been out to try making a recording. The iPhone only just picks the noise up, but now I can't get through the company firewall to upload the file anywhere. I'll post a link to the sound file when I get home.
It certainly doesn't sound like my diff is about to grenade; it's just not quite as quiet as it used to be.
Edited to add: The car is looked after by a highly respected TVR specialist, whose name refers to the cylinder layout of the six-cylinder TVR engines. So it would be unlike them to drop the ball.
It certainly doesn't sound like my diff is about to grenade; it's just not quite as quiet as it used to be.
Edited to add: The car is looked after by a highly respected TVR specialist, whose name refers to the cylinder layout of the six-cylinder TVR engines. So it would be unlike them to drop the ball.
Edited by Dr Mike Oxgreen on Thursday 26th September 13:30
Does this link work...?
https://skydrive.live.com/redir.aspx?cid=f07105117...
If you can play this file, it's a short clip of me driving at low-ish speeds, up to about 40 mph. You can hear the noise I'm talking about from about 20 seconds in, and it's perhaps more prominent on the over-run.
Am I just being an automotive hypochondriac?
https://skydrive.live.com/redir.aspx?cid=f07105117...
If you can play this file, it's a short clip of me driving at low-ish speeds, up to about 40 mph. You can hear the noise I'm talking about from about 20 seconds in, and it's perhaps more prominent on the over-run.
Am I just being an automotive hypochondriac?
Dr Mike Oxgreen said:
I've just been out to try making a recording. The iPhone only just picks the noise up, but now I can't get through the company firewall to upload the file anywhere. I'll post a link to the sound file when I get home.
It certainly doesn't sound like my diff is about to grenade; it's just not quite as quiet as it used to be.
The pinion bearings wear 1st causing misalignment (no matter how small) of the pinion to crown-wheel mesh this then creates the singing/whining you can hear It certainly doesn't sound like my diff is about to grenade; it's just not quite as quiet as it used to be.
although it could be worth checking that the input drive flange nut as not come loose 1st 
wheel bearings tend to drone for comparison 
I haven't noticed it leaking, but the car sits on a gravel driveway most of the time so I don't necessarily notice minor leaks.
Has anyone managed to play the recording? Any thoughts on whether the sound is normal?
Also, how easy is it to put a litre or two of oil in there?
Has anyone managed to play the recording? Any thoughts on whether the sound is normal?
Also, how easy is it to put a litre or two of oil in there?
Edited by Dr Mike Oxgreen on Friday 27th September 06:27
My father-in-law and I have had the car up on blocks to take a look, and it is clearly leaking substantially from the front seal. I therefore think the diff is low on oil.
As it happens, I'm taking it to my local (non-TVR) indie for a pair of rear tyres soon, so I'll ask him to at least top it up with oil - and if he reckons he can do the seal then I'll tell him to go ahead.
We couldn't see a drain plug or a filler plug on the diff. Is there just a single plug for both draining (via syphon?) and filling, or are there two plugs? In either case, where are they? What car does the diff come from? Anyone know what quantity of oil, and what grade?
If anyone can offer any tips that I can pass on to my indie mechanic I'd be grateful. If he were to attempt to replace the front seal, how much disassembly is required to gain access? Will he have to drop the exhaust? Or is this a task best left to a TVR specialist?
It's a '99 450, if that makes any difference. Many thanks!
As it happens, I'm taking it to my local (non-TVR) indie for a pair of rear tyres soon, so I'll ask him to at least top it up with oil - and if he reckons he can do the seal then I'll tell him to go ahead.
We couldn't see a drain plug or a filler plug on the diff. Is there just a single plug for both draining (via syphon?) and filling, or are there two plugs? In either case, where are they? What car does the diff come from? Anyone know what quantity of oil, and what grade?
If anyone can offer any tips that I can pass on to my indie mechanic I'd be grateful. If he were to attempt to replace the front seal, how much disassembly is required to gain access? Will he have to drop the exhaust? Or is this a task best left to a TVR specialist?
It's a '99 450, if that makes any difference. Many thanks!
The pattern of spattering, together with a baked-on trail of oil on the exhaust, makes it clear that the oil's coming from the front of the diff. The singing sound is also coming from behind, right where the diff is.
If anyone can offer some tips for replenishing the oil and/or replacing the front seal that I can pass on to my non-specialist mechanic I'd be very grateful!
If anyone can offer some tips for replenishing the oil and/or replacing the front seal that I can pass on to my non-specialist mechanic I'd be very grateful!
There's a breather pipe? Where's that, and what would cause oil to come out of it?
And from your comment, there must be both a filler and a drainer - but we couldn't see either! (Mind you, we only had the car up on a couple of blocks of wood, so it was difficult to see much.)
Is the filler hole positioned so that you can't overfill it, or do you need to know how much oil to put in?
And from your comment, there must be both a filler and a drainer - but we couldn't see either! (Mind you, we only had the car up on a couple of blocks of wood, so it was difficult to see much.)
Is the filler hole positioned so that you can't overfill it, or do you need to know how much oil to put in?
What make diff is it? If a BTR, the filler is right in front of the drivers side half shaft flange... you'll need a slim spanner to get on it but easy enough with car on ramps or wheel off. The drain on a BTR is the bottom fastener on the rear face plate. Morris Lodexol 75 or 80/140 is the same formulation as the obsolete Mobil product that is recommended. Oil is different for a GKN diff
Gassing Station | Chimaera | Top of Page | What's New | My Stuff