I'm rebuilding the gear box and when disassembling the valve spool pieces, I noticed there are grooves in the worm shaft and spool valve has them along with the torsion rod. The spool valve will slide and spin down the torsion rod when not assembled but will not when assembled. First reassembly lead to steering system turning full lock left. All back apart and know it is something I did wrong with this assembly just not sure how it assembles to function properly. Please help.