It's quite possible you have an overly loose drive pulley belt causing the squealing under deceleration!
Suggest you remove the front pulley cover and inspect the (2) UHW slider rollers for signs of contact with the back of the pulley belt


It's quite possible you have an overly loose drive pulley belt causing the squealing under deceleration!.................... Also, it's squealing using it for compression braking! So I've ordered the Barnett kit.