@Onca Engineering
By top hat and core I meant the housing, sorry for the confusion. Sealant is clear!
My diff does not produce any noises, if the bearings will be bad I think I will give up and send the diff to an expert on this.
So you say with RacingDiff plates and OEM Belleville washer even if mathematically this setup is thicker than OEM because of plates) the more preload should not be a problem? Or the Belleville washer gets thinner with mileage and the more thick plates will compensate for that?

 

@J444G
Correct on your last statement.
The stack up of "fresh" plates with the OEM Belleville seems to result in the correct break away torque of about 70-80 ft-lbs.
The "worn" OEM friction plates probably resulted in a low break away torque. I don't know, as I have only ever seen one OEM LSD with functioning friction plates, and I didn't think to measure it's break away torque.

 

@Onca Engineering my mechanic guy was surprised that the RacingDiff plates have no grooves for oil to get out from between the plates... Do you anything about this, should this be an issue?

 

Hmm. I am a bit confused. The discs offered by RacingDiffs that I spec'd for the Jaguar V6S LSD do have grooves (see photo below). RacingDiffs offers other discs with similar grooves for BMW, Mercedes, and Porsche applications.
Other discs they sell are solid, others have circular holes in them. I am no expert on oil management of friction discs that exist in oil baths so I can't comment further.
But the moly ceramic replacement discs return the LSD action and they seem to offer good service life which is better than the original Jaguar CF friction discs.
/products/jaguar-f-type-lsd-rebuild-kit

 

Yeah I am not expert on this also. The mechanic says the grooves should to to outside, like a canal - therefore not be holes, just grooves similar to slotted brakes. But to be honest he is not expert on this also, just that he never saw this.
Did you actually drive/track with these or did you go to Quaife?

 

My personal car is equipped with a Quaife ATB rear diff which is driven on track, AutoX and street.
I lead the development process for this maintenance free solution and I have recently helped Simply Performance UK to offer this upgrade to the international Jag community.

To support the V6 S community with LSD’s, I worked with RacingDiffs to produce quality replacement parts.
The grooves probably allow for some accumulation of oil to help with lubrication, reduced friction wear, and temperature control.
The periods of axle torque relaxation probably allow for some percent exchange of oil from the grooves with the oil reservoir.
If the groove went all the way to the edge, then the disc would probably be at risk of distorting and failing.