re oil in gearbox --this item has cost thousands of people around the world dearly --it is not as simple as it looks , if you buy ATF by the barrel you will find there are 3 common grades sold of MINERAL OIL ATF !!! a totally different animal to the synth lifetime BMW oil .
if you were daft enough or unlucky that somebody was short a few liters of engine oil for your service and looked around for any solution to get the car out and said who will ever know what i put in or care as long as the low oil light is out --you are in for a treat as in order to get a gearbox to grip clutch discs in a compressed clutch pack you need fricton enhancer which is the oppisite of engine oil -- do you think anybody would admit it however an oil sample will spill the beans and the copper and the steel . take care and the man who showed you the haynes manual knows what he is doing well done - bugs