A cap acting as a grease retention feature and venting system allows crash optimization of a propeller shaft with a plunging constant velocity joint. The cap is located between a constant velocity joint and a tube of the propeller shaft system. The cap includes: a rim sealed against the inner diameter of the constant velocity joint, an interior vent chamber, a vent hole facing the interior components of the constant velocity joint and leading to the vent chamber, and an annular radial groove along the entire circumference connected to the vent chamber. The outer race has a hole perpendicular to the joint axis to complete venting to the atmosphere. In the event of a vehicle crash, the constant velocity internal joint components contact the device, causing the device to dislodge from its fixed position, contact the friction weld curls and fracture at a determined load.