Whirlpool Part
I have a Whirlpool washer which only goes through the wash cycle now and then just stops.?

I was told it may be the switch. I have another Whirlpool that the belt broke on. The part numbers are 3955355 (the one that only washes) & 3956984 (the one with a broke belt). Can the part from the one that has the broke belt fit the other washer (one that only washes). Thanks in advance for any info!!

The numbers you have given are control panel part numbers. What we need is the model numbers. They may be located under the lid at the back of the top, or on the back of the machine (metal plate secured by 2 rivets)

As there are a number of models for Whirlpool, you chances of the timer being the same for both machines is really remote. You could have the timer rebuilt for about $ 70 which is probably the route you will have to go if your machine has a belt on it as it will be in excess of 20 years old. Contact your local appliance parts store and see if they offer that service.