HELP! Noisy Diff After Oil Change :(

[Deleted Member S]

Help i've got a noise after changing the rear diff oil. I put in Cmma LS80W-90GLS (limited slip diff oil) as have other members :? My drive is on a very slight slope so I leveled the T2 on wood blocks (used a spirit level on chassis) &drained the diff untill last drip came out, oil was very dark gray almost black 8O & just a few fragments on the plug. Refilled it & it took all 3 litres 8O
I have checked how much came out about 2.8- 2.9L. Could i've put a bit to much in :? after the run the diff seemed hot :? I'm not sure if it's the diff it's self or the sound is comming fron the breather pipe :? sound only seems to happen under load when increasing speed in all gears.
Has this happened to anyone else or have I killed my diff :?

 

[rustic]

Hi when I changed my oil I put in exactly the same oil, in fact mine took all the 3 litres as well, and my Mav was in the garage on a flat and level floor. My oil was as grey as graphite as well.
Are your tyres on the rear the same type, pressure and more importantly the same tread depth, if not it may take a while for the oil to clean the friction pads in the diff.
The diff does get warm in normal use but you should be able to touch it.
If your tyres are different it will heat up the diff more.
The Breather for the diff goes to the front of the vehicle, it connects to the gearbox vent ( I think) before popping up under the bonnet on the drivers side near the bulkhead, the pipe points downwards.

What sort of noise is it ?


hope this helps..

 

[Deleted Member S]

My tyres are the same ie make, tepth & preasure, I swopped them over n/s to o/s as the tread blocks had a slight shamfer on then, so swapped them over to resquare the tread blocks up.
The noise is very slightly metalic but more of a shhhhhhhh as if it was preasurised I know it's not the best description it's just hard to put it in words. I've just took out about 100 mills of oil & going to road test it again

 

[rustic]

just a quick thought, it's not the tyres them selves is it.. The tyres are each running in the opposite direction and the wear on the tread is different, if all else fails. swop them back.

 

[Terranosaurus]

You shouldn't swap tyres side to side as the carcase "wears in" to the direction of rotation, swap front to back if you want to swap them.

 

[Deleted Member S]

I've been running the tyres this way for about a week now. The noise has only come on after changing the diff oil. Just took it out for a 5 mile run & still the same, I had a better lissen & it sounds like the gears making contact with each other.
Sorry if it seems i'm ranting, just a bit fed up now I have even thourght of putting the old oil back in to shut it up :roll:

 

[Deleted Member S]

Well i've been out & swaped the tyres back over & it's just the same. I'm wondering if it's been run with the old oil for so long that there could be problems with the diff now that it's got the proper stuff in :? :? :?
This has got me stumped as it's only done 65k :roll:

 

[rustic]

It may be possible that the previous oil was not LSD, some Nissan dealers don't fill with the correct oil...
I'm not sure what the consequences are by putting LSD oil in after ..
Maybe some other members can advise..

Just a point.. you did put the plug with the magnet in the drain at the bottom and not in the back of the diff... ie the plug isn't catching the crown wheel in the diff? just thought I'd ask..

 

[JonathanM]

The axle breather on the rear diff doesn't vent to the engine bay, it is a small silicone release flap under the little know on the right hadn side of the upper axle casing. It won't be that, the noise from such a valve isn't audible over road noise.

Can I suggest cghanging the diff oil again, if the original stuff was in such a bad state then the first change will flush out more rubbish, a secong change might help matter more.

 

[Deleted Member S]

Just a point.. you did put the plug with the magnet in the drain at the bottom and not in the back of the diff... ie the plug isn't catching the crown wheel in the diff? just thought I'd ask..

No I put them in the proper holes :smile: I don't know why but i've got a feeling this simple oil change is going to end up costing me an arm, leg & a few orgains

 

[Toolbox]

Sweety,

If you found no great amount of metal particles in the oil when you drained it down, how can it be worn out or damaged now. Get under and rock the pinion shaft via the prop this will tell you if you have a problem with the crown wheel to pinion mesh. You should have a little backlash not a lot.

 

[wolf]

get it checked fast my t2 did not have LSD oil in itl and it was seeping past seals, by time i realised it too late diff was wrecked. jus have my t2 back today after a long wait and several hundred euro ( over 8 )

 

[Deleted Member S]

Sweety,

If you found no great amount of metal particles in the oil when you drained it down, how can it be worn out or damaged now. Get under and rock the pinion shaft via the prop this will tell you if you have a problem with the crown wheel to pinion mesh. You should have a little backlash not a lot.

I see what you are getting at Toolbox, i'm a bit of a worrier I found 1 sliver on the plg about 7mm long, 2mm wide & about 1/4mm thick.I'm not worried about that as I used to get loads on the sump plug of my old metro(A+ engine).I have checked the backlash & it only moves a couple of mm. I'm wondering if the diff bearings are kicking up a fuss :?
I would not have any luck if it was'nt for all my bad luck :lol:

 

[Terranosaurus]

I wonder if this is just normal plate LSD noise. If the oil that was in the difff before wasn't LSD oil, the diff wouldn't have been locking so you wouldn't have heard any noise before as the plates would have been slipping easily against each other. With the change of oil the plates will now be working, but it is not quite true that they lock. They are friction plates (like a clutch) that drag against each other. They will tolerate a certain amount of mismatch in rotation speed of the shafts but as the difference increases the plates start to drag against each other which causes torque to be applied to both wheels, the greater the mismatch in wheel speed the greater the torque that will be applied to the slower wheel (with an open diff less torque is applied to the slower wheel), this really only happens when power is being applied.

So what you are haring may well be the normal operation of the diff, that is now working and wasn't before. You need to get someone familiar with LSD axles to listen to it.

 

[Deleted Member S]

It seems ok on roundabouts :? But on the straight it's noisy, driving at 60-70 in 5th you can hear it & if you drop down to 4th at 60mph it's really loud.
Iwould just like to say thank you to all of you's who are trying to help me out with this :smile:

 

[rustic]

It seems ok on roundabouts :? But on the straight it's noisy, driving at 60-70 in 5th you can hear it & if you drop down to 4th at 60mph it's really loud.
Iwould just like to say thank you to all of you's who are trying to help me out with this :smile:

I'd be tempted to drive in figure of 8's on a quiet car park, that way it should make the LSD friction pads slip past each other and get more oil in and purge out all the gunge. Also try doing same in reverse.
It may take a while for the additives to get to the right part.

Seems very odd.. as per previous hints.. maybe you didn't have LSD oil in before..
Maybe the previous owner had same problem so put in a different grade of oil !!

 

[Deleted Member S]

I will give that a try later :smile: Mind you the last time I did figure of 8's I got nicked by the police :evil: Saying that I was sideways in my Capri :lol: :lol: :lol: It's off to the garage in the morning to get checked over, so there go's 1 arm & both legs

 

[Deleted Member S]

Well heres the update, just got it back from garage & I should try an addative in the diff to see if that shuts it up as the last owner may have done this :roll: They think the noise may be from the bearing.
I went to halfords to see if I could get some molyslip or alike but every thing was for none LSD :evil: Can anyone recomend some where to get some. You'll all strike me down for this :lol: My other thourght was to replace a litre of oil with the old stuff after being filtered well a few times

 

[rustic]

Can anyone recomend some where to get some.

I used Molyslip G and Multiglide in the gearbox and Richard at Silverstone recomended putting "another 100 ml of Multiglide in the rear diff as it should be a LSD" so it should be compatible... but check first..

I haven't done this myself as the rear diff is ok.
But the aditives worked great in the gearbox..

You can contact Richard, see Molyslip thread in the forums, or go to his site on ebay at Crewchiefs-pitstop&molyslip-shop, you will find the site if you search for Molyslip or Multiglide.

Ask the question what is recommended for your problem and they will get back to you quickly. I understand that there is club discount and they are very helpful indeed.
I hope this helps,
best regards, Rustic

 

[Deleted Member S]

Cheers for that Rustic I will get in touch with him as this is doing my head in