Jandre, that is insanely cheap man.
I paid just short of 800 just for the OEM filter from BMW.
And I can promise you that they are not using OEM oil, cause the OEM oil is like R1,000 a litre or something, however that is not a bad thing, plenty of other cheaper oils that are higher rated then the Shell LA 2632, which is the manuf. recommendation.
Yea, its R1400 bucks gone, but its perhaps a gamble, and I would say if the whine is intermittend, you may still have a chance.
That said, the gearbox does have 240+ on it... so its a gamble, but it is not that expensive, and then at least you will know, also, buying a scrapyard box is also a massive risk, you dont know what you are buying..