This article presents analysis of the first order Coriolis resonance between the nondegenerate and degenerate normal modes of the symmetric-top molecules leading to the doubling the sublevels of degenerate mode with the quantum number values of full and vibrational angular momentum projection equal to unity (k = l = ±1) at strong rotational disturbance. The effective Hamiltonian for "giant l-type doubling" Hg.d has been constructed based on the theory of coupled schemes for grouping the vibration-rotation interactions. Theory of nonlinear series transformation has been applied to analysis of the series over J2 obtained in Hg.d. The first diagonal Pade approximant for the vibrational dependence of the giant l-type doubling is presented. The diagonal Pade approximants of a higher order are presented, in particular the [2/2] one, in terms of the series expansion coefficients for the investigated rotational dependence of the giant l-type doubling on J2. The relationships have been derived for the parameters in Herman-Wallis factors in terms of molecular constants for the case of strong, (νA, νE), Coriolis resonance. Numerical estimates in the Herman-Wallis factors for the CH4, OCS, CO2, and HCN molecules are presented.