Recent X-ray observations by Fermi/GBM discovered a new torque reversal of 4U 1626–67 after 18 years of steady spinning down .
Using Swift/BAT observations we were able to center this new torque reversal on Feb 4 2008 , lasting approximately 150 days .
From 2004 up to the end of 2007 , the spin–down rate averaged at a mean rate of \sim \dot { \nu } = -4.8 \times 10 ^ { -13 } Hz s ^ { -1 } until the torque reversal reported here .
Since then it has been following a steady spin–up at a mean rate of \sim \dot { \nu } = 4 \times 10 ^ { -13 } Hz s ^ { -1 } .
The properties of this torque reversal , as well as the lack of correlation between the X-ray flux and the torque applied to the neutron star before this transition , challenges our understanding of the physical mechanisms operating in this system .