LSD chatter???

Hi all,

Today I drained and replaced fluid in the rear diff on the Jackaroo. I used Castrol's LSX85W140, but didn't put in any LSD additive.

Now there's an occasional deep buzzing noise that comes from the rear. It's intermitten and usually under hard acceleration just before the transmission shifts up. Can be either in a corner or a straight.

As I have never heard LSD chatter, I don't know if that is what it is and whether I should be adding the additive as per Holden's recommendations. I note a number of fellas here have put in straight LSD fluid into their Jackaroos without the additive and have had no problems.

Also, not sure whether it might be overfilled. The car was up on ramps at the time and so it wasn't level. About 3.5 litres went into the diff where the specs say capacity is 3 litres, but there was no overflow running out. I'll get under it tomorrow morning while it is on a flat and see if anything runs out when I open the filler.

Any hints on the buzz, guys?