machine is popping while spinning wont spin at full speed

machine started popping while on spin cycle. It will not spin at full speed. Clothes are soaked. I installed a new thrust bearing kit part number 2100 1734. It will not go into proper alignment with the shims. With the small shim. 032 thickness it is below the minimum pulley hub reference. I removed all the shims and it is aligned perfectly between the two marks.I tried it again and it is spinning at full speed but then pops again and slows then goes back to full speed then pops and slows.it is a little better but it is still not right. I’m starting to wonder if its the transmission. Any help would be appreciated I’m about to just throw it out the back door and go buy a new one.thanks.