LSD noise in my CV8 manual??

[madmartin]

Hi guys, due to an excessive backlash issue with the Diff in my CV8 I've just fitted another from a VX SS i brought second hand. Being a manual they're not easy to find the right ratio, so when i found one i grabbed it. Fitted it up this afternoon, filled it with 75/140 fully syn oil plus additive and took it for a drive.

So now i can hear what seems to be a metallic grinding noise at low speeds. There was no noticeable play in any of the bearings and the oil that came out of it, although reasonably black had no major contamination.

Anybody have any ideas what i might be hearing?

There's no clunks getting on and off the power like the old one and it doesn't have the diff while I've heard in the past from my previous holdens, but it's still somewhat unnerving. My knowledge of these things is somewhat limited so interested in any thoughts.

 

[Turtl3]

jack the back of the car up and spin the wheels by hand, then get someone to hold one wheel or lower one side to the ground and spin the one thats still in the air. thats the only downside to buying second hand gear...u just dont know what kind of a life its had.

it could just be a brake dragging but hard to say...could be gearbox...wheel bearing?

 

[madmartin]

the old diff ran pretty quietly, once the backlash clunk had happened there were no other noises going on. I reckon what i'm hearing must be coming from the replcement unit.

Couldn't feel any play in any of the external parts when i fitted it, but there's still stuff inside there that could be making this noise, it's almost like a chatter if that helps?

 

[Turtl3]

the factory lsds arent renowned for their strength. personally i wouldnt reuse a diff without atleast opening the centre and having a look at the thrust washers/clutches/side and spider gears. does the noise get worse if you turn the car in tight circles?

 

[madmartin]

It seems to be most noticeable at low speed, the road noise in the cabin kinda cancels it out over about 60kph.

The noise is no worse when turning, but i haven't tried a CV type turning test with tight corners.

It's not overly loud, but there's something there, more noticeable on smooth roads certainly. Maybe grumble is a better word to describe it.

 

[Turtl3]

well if you dont want to risk destroying the crownwheel and pinion...i would suggest pulling it out and having it overhauled. hopefully just bearings and clutches

 

[BOOSTER]

The oil wears with the diff, you could tip the old oil back in it.

 

[madmartin]

Sadly I might have to suck it up and pay to have it rebuilt. Hate to think what that's gonna cost

 

[BOOSTER]

Always re-use your diff oil, you can top them up but you can't change the oil.

 

[madmartin]

There wasn't enough oil to make it worthwhile. It's been filled with correct oil and GM additive