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We present a comprehensive analysis of X-ray pulsar 4U 1626-67 during itscurrent spin-down (2SD) state, following a recent torque reversal. Since itsdiscovery, this ultra-compact binary has experienced multiple torque states,transitioning from spin-up (1SU) during 1977-1990 to spin-down (1SD) during1990-2008, and again spin-up (2SU) until 2023. From NuSTAR observation of May2023, we have investigated the timing and spectral properties of this pulsarduring its 2SD phase, while also comparing them with previous spin-up-downstates. For energies upto 8 keV, a distinct bi-horned pulse profile wasobserved during the spin-up phase, while several sub-structures emerged duringspin-down. Beyond 8 keV, a broad asymmetric peak was consistently observedacross all torque states. The pulse fraction during the 2SD phase was higherthan that during 2SU phase. A prominent ~46.8 mHz quasi-periodic oscillationhas been exclusively detected during the spin-down phase. The broadbandspectrum during the 2SD phase is described by empirical NPEX model, cyclotronabsorption feature and its first harmonic. The spectrum during 2SU phaserequires an additional blackbody component and asymmetry in the cyclotronabsorption line. A significant flux drop by a factor of ~3 in the 2SD wasobserved.

4U 1626-67 Returns to Spin-Down: Timing features toe the line