I love my Grasshopper and I have a 2003 321D that is the best mower I have ever had. Built like a tank with 537 hrs on the clock. It has developed a weird oscillating noise with the mower engaged. Sounds kind of like a blade is hitting a shroud in the round sheet metal surrounding one of the blades. I don't see anything and it comes and goes while the mower is running. About +/- 3 second intervals. All spindles and blades are tight. None of the idlers appear to be worn or loose. Has anybody ever seen anything like this, if so what was the cause?? Don't feel comfortable waiting until something breaks or falls off! Any help appreciated. TIA
321D Weird deck noise
- Thread starter Maskedman
- Start date
mechanic mark
Lawn Pro
I would remove deck for cleaning & inspection.
What @mechanic mark said. 
Oscillating? Something that’s spinning is making the noise. You are going to need the deck belt off and spin all of the pulleys and idlers. Check the play in the spindles.
Also, check your belt. There could be chunks of rubber missing from the belt.
Oscillating? Something that’s spinning is making the noise. You are going to need the deck belt off and spin all of the pulleys and idlers. Check the play in the spindles.
Also, check your belt. There could be chunks of rubber missing from the belt.
This is a very broad statement. I don't need a general answer. I was looking for someone who had experienced the same kind of problem for a specific answer. Thanks
Tiger Small Engine
Lawn Addict
Check to see if your blades are hitting under the deck.
SeniorCitizen
Lawn Addict
I don' have a specific answer but if you still have the old blades reinstall those . If the noise stops we can be reasonable sure the noise has something to do with the new blades
I never changed the blades but no they are not hitting.
You are going to have to remove the deck and give it a good inspection. There is no way to check for proper spindle condition with the deck mounted. I’m guessing a bad spindle bearing which shows itself during operation. Second, when you have the deck off you can really go through it to see if there is any metal to metal contact.
SeniorCitizen
Lawn Addict
If there;s a bad bearing that bearing assembly be a warmer temperature than one with good bearings . Kill it and feel them after it runs awhile and the noise starts .