How can i clean the tub of my amana NTW4631BQ

The problem may be the seal on the transmission failing. If this happens, grease from the transmission (necessary for it to function) will leak and float (recall from science class that oil is less dense that water) up into the washer. As the grease enters the tub, it stains your clothes.
Washer Transmission Replacement Whirlpool Kenmore Top Load Washing Machine...

Washer Leaks Water GE Top Load Washer Tub Seal Replacement Part WH02X10383

Oh, that's not good.
If you turned your washer over to check out the lower end, some of the transmission oil will leak into the tub. You may never do another clean load.

after parts replaced

you can still by a new drum and outer shell for that machine
main shell of washer
main shell plastic or metal

http://www.appliancepartspros.com/parts-for-amana-nav3335aww.html

grease may be trapped between inner drum and
if taking apart steam/pressure clean between the drum and internal
use full container of borax
use very hot water
and run an empty full load wash

actually sounds like fabric softener residue with dirt mixed in...it's almost like a wax if thats it. probably just have to clean it regularly..good luck! :)

The problem is with the motor over heating It should be taken apart & cleaned, the motor is over heating,If ater you clean out the lint It still does the same thing Its the motor

hi thanks for the question if you cleaned the screen and no hot water i would replace the water valve thanks the appliance doc

Try this for you timer.
That is if you are handy and can open the washer to work on it.
UNPLUG FIRST!

Just carefully clean all the contacts and put contact grease on them.

you may have blockage in the drain pipe several feet from washer. if you can run spin cycle with hose in different location ex. tub,sink or outdoors. if this works run long snake down washer drain pipe to clean gypsum residual.

A good marine type silicone sealant (like what you might use on boats) might buy you some time. However, with the vibration of the machine and the torque applied to the tub when the transmission and drive motor engage to spin will only make the crack worse over time. Sorry, but you might want to think about replacing the tub.

Cylon, sounds like you need to replace the water inlet valve. It's not seating and weeping water. For series 10 the part number would be 40097701. Not that hard of a job. Catriver..post back.