Castrol syntethic Limited slip gear oil

[Nacho-RT74]

is any good for clutch kind Suregrips ? casuality I found these being sold locally

instead use the aditive which is unavailable locally

[Paul G]

Synthetic did not work for me. It made strange noises come from the rear end. I switched it out for regular gear oil and limited slip additive. Nice and quiet now.

[Nacho-RT74]

ouch!...

more opinions please

[shart70rt]

Same for me.

Mancini had limited slip additive when I switched a year ago.

[Nacho-RT74]

I don't live in USA and I never have being able to get the aditive locally ( have couple of bottles storeaged though ), so, was thinking on this

[A383Wing]

no matter what rear end lube you use, you will still need the additive.....the synthetic by itself is not enough...even if it says so on the bottle

[NHCharger]

Nacho- I replaced whatever oil that was in the rear end of my 68 with Royal Purple Synthetic. I did an initial road test of 1 mile. The next morning there is oil leaking out the front of the yoke. The rear end was bought from a friend of mine 13 years ago when a previous owner had started the restore. The sales slip claimed the rear end was rebuilt (I have my doubts since I know the seller).
I drained the Royal Purple and replaced with dino oil. Valvoline 85/140, with  small bottle of the additive. 12 mile test drive on Sunday morning. No leak.

[John_Kunkel]

no matter what rear end lube you use, you will still need the additive.....the synthetic by itself is not enough...even if it says so on the bottle

In recent years I've used nothing but synthetic straight from the bottle...no extra additives and no clutch chatter.

[Paul G]

I wonder if the difference is cone type or clutch type diffs? Mine is cone type.