A fair amount of the stacks I encounter do already have the upgraded wax motor from the factory. Go figure. Your spin issue could be one of a few things depending on what it's doing.
A) it drains and tumbles but will not spin. Instead, it just tumbles back and forth until the spin cycle times out. This usually indicates an issue with the spin enable switch not being read by the control board. It thinks the door is unlocked and will not ramp up. It could be either the dreaded blown wax motor and board not locking the door and hitting the spin enable switch (indicated by the door lock light never coming on) or the door is locking but tumbling to and fro when it should be spinning which would indicate a possible bad spin enable switch. The weird thing is that the switch will usually read good with a meter but will still not let the board sense a door closed condition. It's that sensitive.
B) it starts to ramp up on speed, maybe even reaching a slight fast speed then immediately stopping and going into a unbalance condition. This is where it thinks its unbalanced due to a opening of the unbalance circuit, slows down, tumbles back and forth a couple three times then attempts a ramp up in spin speed. This is normal EXCEPT when it does this constantly, over and over and never reaches high speed. If it does this every once in a blue moon, then it may just be a load that it just doesn't like. Something like a single pillow, for example. It just can't balance that and gives up. It tumbles back and forth, draining what it can, then shuts down at the cycle's end.
Now if it does it consistently with every load, then you most likely have an issue with the unbalance circuit. There are three switches that tell the computer if the load is unbalanced. The very first ones had a little switch mounted on the back left strut and a tub impact switch on the right hand of the tub and a inertial switch right above that. Later models had the strut switch removed and replaced with a switch mounted at the bottom of the counter weight at the bottom of the tub and the inertial switch was moved to the top of the tub. The last generation had the inertial switch completely removed as it was a weak link in the circuit and caused a few false trips. For those who don't know, the impact switches opened the circuit if the tub was unbalanced enough to make contact with the cabinet side or bottom and the inertial opened if the tub shook enough but didn't impact with the cabinet. Actually a decent system that wasn't at touchy as the ones now that just sense by motor torque.
Anyway, one of the switches could be bad or, even simpler still, a wire may be broken at one of the switches from the wires vibrating as they could have been better secured.
Sorry for the long winded explanation. I try to explain something and get lost in the fun...
RCD
