Usually, you need to adjust the secondary to give the belt a bit more deflection. On the P85 secondary, you will need to loosen the three bolts on the external adjuster and adjust to allow the belt to slide slightly into the clutch. The squeal is normally caused by the belt rubbing on the center of the primary because the belt is too tight.
The standard L tool which comes standard on those machine with A Team driven can be used on your secondary if you have one. Remove 1 of the 3/8" bolts that hold the adjustment ring (gold color) on the secondary and the tool will thread into the hole and open the sheaves. That tool has a standard 1/4"x20 thread.
I remember Polaris using the P85 up until 2003. When they got PERC, they had a Polaris roller clutch for a while, then started using Team with the reverse-capable helix in the secondary so it would work in reverse.
A lot of mountain guys switched to the Team on their Edge RMK's (me included) to take advantage of the better backshifting secondary.