It could be a main tub bearing, but check out other possibilities first, the water pump can sometimes make a funny noise. Try taking the belt off the water pump and put the machine in the spin cycle to see if the sound goes away. It might just be a noisy pump.
Should be lubricated with turbine oil upon installation once everything is assembled before you put the mounting stem back in place fill the groove at the top of the bearing with turbine oil as well.