The tub seal can't be seen or checked without dismantling the machine. All you can do is remove panel on back of machine & watch while it is doing a wash cycle. See if you can tell where the water leaks from. Could be a hose, the drain pump, hole in plastic bowl. If it appears to come from above the pulley & gearbox then it will be the tub seal gone and machine will have to be dismantled. If it is this seal you will usually have a very noisy spin and signs of brown rusty water stains splashed around inside of lower cabinet walls.
Lincon Appliance NZ, April 2013
