We have 2 2003 trailboss 330s, They both have about 600-700 miles on them. They both make the same noises
from the transmissions when under a load, usually on an incline, but sometimes on level ground also. Noise sounds like grinding / vibration, They both started doing it around the same time. Fliuds have been changed on schedule and checked before each ride.

 

Mine makes the same exact noise and the dealer said they all do it. I thaught it was the same tranny in my Trailblazer and my blazer does not make the noise. I guess it wouldnt be a Polaris without a noise.

 

well if both your Trailboss' are doing it then i guess it should be somewhat normal lol. my polaris makes alot of noise too but im getting used to it

 

I have an 03 Boss and my brother has the 04. His makes the noise more than mine. I think it's the chain guard rubbing the chain or rear sprocket. to tell the truth I remember it as one of those two things. The noise is hard to adjust out by moving the chain guard. Make sure your chain is tight. They have to be pretty tight on the concentric drives like yours. Have someone bounce in your seat and watch the guard move and see if you can tell?

 

We originally thought it might be the chain guard too, after removing it from one of them, it still made the noises.
It sounds like it is in the transmission. Is it possible there might be something in the trannys that vibrate under
a load, or climbing a hill ? Could I try a different fluid ? We go to Wayne National Forest a few times a year, and have not heard any other Polaris's making this kind of noises.

 

OK. Chains tight, guard removed and still makes the noise. I don't know - I can't help but think chain. My dealer will go out and ride too. Perhaps you can meet him or one of the shop guys out on a ride? I know it's hard to have it make the noise in the dealers yard. Good luck.