You dont say wether its front or rear shaft. however the rear shafts are all same except rwd sierra cos which use bigger cv joints and thicker shafts, i assume its probably front as these usually give trouble. the escos and sierra cos4x4 are same but v6 sierra 4x4 use longer shaft (10mm) but same joints, however many people use longer shaft especially on very low cars as the increased angle on the shaft as the suspension is loaded can cause damage to joints and even pull apart completely especially if the engine mounts are tired. check the engine mounts before replacing or you could be replacing again very quickly.