Grinding from CV axle after replaced

Welcome to 2CarPros.

You have not fully engaged the inner axle spline into the transmission or into the front hub assembly on one or both sides.

I attached two pics and circled the areas of concern. What you are hearing are the splines trying to mesh. It is the same as taking the drive shaft off a rear wheel drive vehicle. There would be nothing connecting the differential to the transmission. Thus, you have no park and in this case, the splines are turning but not fully engaged.

You need to take it apart and confirm the splines are full engaged.

Since you only replaced one axle, that is the side which is the issue.

Please let me know if you need help and if this helps.

Take care,
Joe