2019 Zforce makes a metal grinding when the gas pedal is released. Some oil is visible in the back of the case, and the short shaft has a ring that appears to have a crack.
Does anyone have an idea what could cause this problem? Is this a DIY fix or repair shop?

Thank You

[2015 Z Force 800 53/Trail EPS]

Because the engines are rubber mounted the drivelines have to have some movement. The front has u-joints and splines but the rear has this coupler between the engine and rear gear case that acts a little bit like a CV joint. Normally they wear at a predictable rate and have to be replaced but there are those with loose engine mounts or bad rubber mounts..or loose rear gear cases that cause failures in this coupler more quickly..yours had not only failed, it's destroyed and has to be replaced. Don't use it any more until fixed as it can damage either or both of the shafts...then you are F'ed. The service manual will show how to remove it but I'll guess the rear gear case has to be loosened and moved forward. At least you don't have that e-brake disk and other parts to deal with like I do. Post pics if you do it yourself...and inspect all that other stuff. It failed for a reason. Find it. One of the seals may well be damaged as well. Hopefully that doesn't mean a shaft is also damaged.