Last weekend i the gearbox slipped into neutral and then at 3k RPM it came back into gear (loose gear shifter BTW Its a auto)

and after it came back into gear and made its loud thud i noticed a noise which to me sounded like diff whine, but more or a whirl to my ears it does it in all 4 gears, i replaced the diff with a 3.45 LSD took it for a test drive noise is still there, i highly doubt this diff has a problem to as the noise has not changed one bit.

i thought maybe wheel bearings but because it happened after the gear slip i thought couldn't be them, my thought is either the uni joints in the tail shaft or something in the gearbox, the gearbox does need about 250 ml of fluid so will be changing fluid even though was done less then 5000 km ago/ 2 months. anyone have any other ideas what it maybe

Planetry gears in the tranny might be.....uuuuummmmm....stuffed.