Step 1: Find the position number of each letter.
In CAB, C is the 3rd letter of the alphabet, A is the 1st, and B is the 2nd.
Step 2: Work out the rule using C.
Square the position: \(3^2 = 9\). Cube that result: \(9^3 = 729\). Then subtract 6: \(729 - 6 = 723\), which matches the code given for C.
Step 3: Check the rule on B.
\(2^2 = 4\), \(4^3 = 64\), \(64 - 6 = 58\), which matches the code given for B. The rule, square the position, cube that answer, then subtract 6, is confirmed.
Step 4: Check the rule on A.
\(1^2 = 1\), \(1^3 = 1\), \(1 - 6 = -5\), which matches the -5 in the CAB code.
Step 5: Apply the rule to D, the new letter in DAD.
D is the 4th letter. \(4^2 = 16\), \(16^3 = 4096\), \(4096 - 6 = 4090\). A still codes to -5 as found in Step 4.
Step 6: Assemble the code for DAD.
D = 4090, A = -5, D = 4090, so DAD is coded as 4090 -5 4090.
Final Answer:
\[ \boxed{4090\ {-5}\ 4090} \]