Maytag Commercial Front Load Washer MAH20PNAWW - replaced the motor because it wouldnt turn - worked fine for 3 weeks. Now the problem is that it will get up to spin speed for 1 out of 5 loads. what c

SOURCE: Front load washer doesn't spin

My Maytag® Neptune® washer filled with water, but it won't spin or drain-what now?

Start by making sure the machine is plugged into a live (working) electrical outlet. Then check the appropriate circuit breaker and reset it if necessary (or check the fuse if you have a fuse box).

Next, inspect the drain hoses and remove any kinks. Take a look at the drain, too - if it's clogged, call your usual drain service person.

Then close the washer door and firmly press the START/STOP button. In a few moments, after the door locks, the washer should begin to spin. (For your safety, the washer will not tumble or spin unless the door is closed and locked.)

If this doesn't work, please contact Customer Service at 1-800-688-9900 for toll-free assistance and service scheduling if necessary.

SOURCE: Maytag MAH20PD washer does not do the High Spin Cycle

with what you have described the problem should be in the door lock unit. there is a check switch that gets pressed down and sends a signal to the computer board telling it that it is locked. if the switch isn't working then that signal will not be sent and the washer will just turn and never enter spin. replace the switch and this will clear up the problem

SOURCE: How do I open my maytag Neptune MAH9700AWW front load washer?

first get access to the back of it. find the screws that hold the accsess panel on unscrew and look underneath. its on the bottom.

SOURCE: maytag coin-op top load wont spin, motor runs, belt burns.

it not a belt, there is a $20 plastic and rubber coupling between the motor and the transmission that has broken.  It needs replacing. 

SOURCE: Maytag Neptune Front Load Washer Model MAH4000AWW low last spin

two problems here,
your shaft seal is running on its last leg
the sound is unmistakeable and always described the same...
the water issue, you probably have a trickle leak through the cold water valve
the mixing valve is quite an easy repair, but I would have to say with all honesty, it probably time for a new machine
the hub seal is a tub replacment call
2 hrs of labor if hes good
and the tub runs around 500.00 dollars
sory for the bad news