LSD Clunking Noise

[Lakeland997]

After a couple of rally seasons running an ATB diff I've just fitted a plate LSD (Swiftune) for 2020.

After running it in for about 50 miles it is very clunky when you turn at parking speeds.
I understand that they do this to some degree but it really sounded like the Hardy Spicers were loose (which they weren't).
I pulled it out to check it over and there's nothing visually amiss.
I understand that oil may have an impact and I'm running it in Castrol R40 so could that be a factor?

I'm awaiting comment back from Swiftune (although it's always hard to diagnose at a distance) but I'd appreciate comments from those of you who are used to running these things.

Andy

[wantafaster1]

Andy
I can't really remember any noise but mine did strange things initially, it settled down quickly, have you tried to make it spin yet?

[r.tec]

One of my Minis is fitted with a Trannex-LSD and at some steer angle it is hardly possible to push the car around and you can hear the LSD working. But driving it under power is really nice.

[Nick W]

Last year I had my ATB changed for a tranex NXG lsd, first time I drove it I was covinced the hole thing must have calapsed ...as the knocks and bangs whilst turning slowly were horrendous.
But, when driven though corners hard all seemed good, so I stuck with it and now after a couple of hill climbs its working fine, and the clunking has diminished some what....I wonder if the pre load was too high to start with. Anyway I now find the car is far more stable on cornering than with the ATB.
also when you no longer here any locking up of the diff when turning slowly ....its probably finished and needs new plates fitting.

Nick

[Oneball]

I can get mine to clunk if I jack it up and turn a wheel but never noticed a mini one clunk while driving.

Have had it on others though and Chevy ones are renowned for it. So much so that the factory starting adding a friction modifier to the diff oil to stop it.

[IanD1965]

I ran one in my mod prod mini for years. No problem and was quiet .I also ran castor based oil , though the silkolene version which has some additives to stop it getting gummed up?

[Lakeland997]

Thanks guys for all your comments.
I’m taking from what you’re saying it shouldn’t be as noisy as it was but it might just be a matter of giving it some proper use to get the plates spinning.
In reality, I’m on a very tight timescale so I’ve ordered an NXG from MED to fit Monday and investigate the Tran-x later.

Andy

[mk1]

A [plate LSD will / should clunk like a bugger at parking speeds.

[mk1coopers]

Could it the be the tyres losing and gaining grip (shuddering) at slow speeds with lock on contributing to the noise as well as the drive train ? , there are a number of modern cars that suffer from a really bad noise at parking speeds that has picked up the technical term of 'crabbing' (even though we would associate that with poor rear subframe alignment) manufacturers seem to be changing from summer to all season tyres (what sort of tyres are you running for the competition work) to try to stop this on customers cars where it's really bad.

Might have nothing to do with it but if you have a spare set of different tyres it might be a easy way of seeing if they are part of the problem

Have a look at this link

https://www.honestjohn.co.uk/news/misce ... g-problem/

[Nick W]

It wasn't the tyres on mine, just the diff unlocking/locking as it ramps up squashing the plates.
I think the med NXG will do the same as the Swiftune one.

[Lakeland997]

You are correct Nick
NXG is exactly the same.
Stick/Slip clunking/juddering at slow speeds. Frees up straight away if you boot it. Makes the steering heavy and manoeuvring very hard work.

Do they get any better with use?

[Nick W]

Yes it will ease off quite a bit after its had some stick, although it seems odd to use at first, once Id used it at Harewood It felt like it was on rails compared with the ATB, and isnt any heavier to use exept when parking etc.

[Hipwell]

A [plate LSD will / should clunk like a bugger at parking speeds.

Isn’t it more clack than clunk?

OP.. What’s the reason for running Castrol then?

[Lakeland997]

Yes, 'clack' would definately describe some of the noises!
You can literally feel the plates locking together then suddenly releasing. It's quite a shock that I wasn't expecting.
Sometimes it locks up the steering and you have to be careful manouvering around tight areas.
Perhaps some more information should come with the diffs to prepare you.

I've only just thrown it around some quiet corners locally but I know what you mean Nick when you say it feels like it's on rails compared with the ATB.
It pulls you round the bend. It's like there's Witchcraft involved.
Clearly though the ATB is the way to go for a road car.

The oil choice is really fulfilling a passion from when I was in my early teens standing at places like the bottom of Hardknot Pass in the middle of the night watching the rally cars go through, many of them Minis, brake discs glowing red and all smelling of Castrol R.

[mk1]

It is in the nature of any good plate LSD that on hard lock at very low speeds it will crack off. As the two driven wheels are moving at appreciably different rates the LSD will do what it is supposed to do & crack & clunk as the wheels are turned. If a plate LSD doesn't display some of this characteristic when a car is moved at very low speeds with the wheels on hard lock, the diff isn't working & needs adjustment.

[jb14p]

I have been running plate diffs for many years, and it’s perfectly normal for the clunk on lock at slow speed so don’t worry. They are an awesome bit of kit, but not for the faint hearted! Enjoy the experience!