Hi Mori

The new couplers have a metal insert in the plastic parts for added strength. This does not affect anything, except it make them harder to get on the shafts of the motor and tranny. Make sure you have them on completely if you did not already do so.

About your noise, it is hard to tell because they way we try to diagnose noise is to listen to it, and well, we can't do that here, can we?

I would operate the machine with the cabinet off (bypass the lid switch with a solid copper wire, ends exposed inserted into the two outer holes of the connector coming from the console) and see if you can narrow it down.

Good luck, let us know if you need more info