Isuzu LSD Binding/Grinding Noise

steve66

Observer
G'Day All,

I've noticed my rear LSD binding up and sounding very loud the last couple of weekends away, it happens when low speed maneuvering after a hot highway drive- ok around town or when colder, the truck is 5 years old but only has 8000km on it, I suspect the additives in the oil may be breaking down. Castrol recommend EPX 85W-140 oil and Add Isuzu LSD additive Part No. 8010523580. First time I've seen Castrol refer to an OEM additive rather than their own LSD oil so must contain something extra?

So thinking of trying that first, any thoughts/experiences?

Cheers Steve
 

steve66

Observer
Thanks Julian, it binds so much it affects the steering, I thought it was the front diff playing up at first!

Hopefully new oil and some magic goo from Isuzu is all that's needed.
 

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Howard70

Adventurer
Thanks Julian, it binds so much it affects the steering, I thought it was the front diff playing up at first!

Hopefully new oil and some magic goo from Isuzu is all that's needed.
Hello Steve:

Like Julian, we've had the same symptoms in two Fuso FG's (a 2014 and a 2017). In both trucks changing the differential fluid with a proper LSD fluid fixed the problem. We'd tried regular differential fluid and added LSD additives which worked, but our longest lasting solution was some LSD fluid sold by Mitsubishi.

Howard Snell
 

yabanja

Explorer
We are very experienced with clutch type limited slips from road race cars. They need friction modifiers. I have found binding on our truck on sharp turns even with the mitsubishi fluid. It can be subtle or obvious but in any case it tends to wear the outer edges of the front tires. I use conventional gear oil(not synthetic as it is too slippery for the clutch packs). I then add two bottles of ford Friction modifier with excellent results. Just don't get it on you as it stinks to high heaven and takes a long time to come off.

Allan
 

steve66

Observer
Thanks Guys, appreciate the feedback, the LSD has always been tight from new but was told to expect that, will go with new oil and bottle of Isuzu additive and take it from there.
 

Karl of Oz

Observer
Had the same thing with my 2016 FGB, particularly after its 1st service when Fuso put the wrong oil in. Made some scary noises but eventually fixed with friction modifiers (Mitsubishi have the right oil) as others indicated above. Still occasionally binds but nothing frightening. All Terrain Warriors have had this experience with both Fuso and Isuzu and apparently its not uncommon.
 

steve66

Observer
Thanks Karl, I picked up some LSD additive from Isuzu yesterday, New part number is 8889003300 about $40 inc, they had a shelf full, 1 bottle per diff he said. that part number also shows up as a Honda product on Google at a cheaper price if anyone wants to save a few bucks.
 

macca4802

New member
My 2016 NPS makes a horrible clunking when turning too. The dealer I bought the truck from new told me it was normal, sold some additive to me which I put in and it hasn't changed. So with a total of 6500 kms on the clock I changed oil in front and back diffs to Penrite 85W-140 gear oil for LSDs. Still no change. Been told by others it's leaf springs moving. Only negative I can find with this truck though. Would love to fix it.
 

steve66

Observer
Hi Macca,

Does it do it when cold or only when hot?, the rear LSD's in these are really tight, mine grumbles a bit when cold (I was told to expect that). It got really bad when hot, I've changed the oil and added the magic stuff from Isuzu, will see how it goes on our Kakadu trip next week.

Changing the oil is not an instant fix, takes a few km's for the additive to work it's way in.

BTW, putting LSD oil in the front diff is a waste of money, not required, but will do no harm.

Cheers Steve
 

macca4802

New member
Hi Steve, yeh mine seems to get worse the warmer it gets. I tried the Isuzu additive which didn't make a 'diff'erence. Dealer told me if I replace the oil with gear oil suitable for LSDs the additive is not required. Also my front diff is an aftermarket ATW LSD. Can't tell which end the shuddering is coming from so I changed oil in both ends. I need to do some more Kms as you say. We'll see.
 

SkiFreak

Expedition Leader
The ATW ATB diff centre does not use clutches, so it is highly unlikely that the noise is coming from there. Also, if there was binding in the front, you would feel it in the steering.
 

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steve66

Observer
The ATW front diff doesn't need LSD oil, just standard stuff. But as I said it doesn't hurt if you use LSD oil.

Mine was so bad last trip I thought it was the front diff as it seemed to affect the steering but that may have just being the potholes in the roadhouse forecourt!

I noticed it again when I came home and pulled in for fuel, so went for a drive around the CBD (lots of slow tight turns) and it went away after a while as it cooled down. I tend to push it pretty hard on the hwy, sit on 110 kmh, so fingers crossed I've fixed it with new oil etc, hopefully yours is the same.

Cheers Steve
 

Spanna 53

Member
Yes Steve mine 2014 was the same changed the oil and added the Izusu LSD additive has been fine ever since 30000 k but will change it again next Service 50000 k if we are ever able to leave the state of confusion and head for the Cape we should be some were North of Cairns by now. Pull up after fifty kms and bang klang as you pulled in and positioned in to the spot some one felt we needed to be drove me siller and did it as soon as we got home
 
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