Tyres screeching

[rustic]

Don't think that when dealers change the oil they put the right stuff in, they don't often sell LSD oil from their spares department. I tried 3 dealers, they said we just put ordinary stuff in..... from that big drum over there....

I had similar problems and used Comma LSD oil 80W90 GL5.
MUST be LSD oil.
As per the other threads, you may need a second change to clear out the wrong oil. When you change the oil, it looks like graphite... silvery grey.. contaminated with the friction material. (this is normal after a few thousand miles).
Also run both rear tyres with the same tread depth and type, same pressures etc and you will notice the difference.
Otherwise the LSD will work over time.
My tyres screech on dry multi-story car parks at very low speed on near full lock. So some screech is normal.
You will need just under 3 litres of LSD oil, a 1/2" wrench, the 1/2" drive fits the plugs as they are. Undo the filler first, half way up the rear diff ( in-case you can't get it out later,) and drain the bottom. You can do this job while it's sat on the drive. No jack required. 20 minute job......Max and that includes 2 cups of tea waiting for the oil to drain. : :
Hope this helps.
best regards, Rustic