The $\ensuremath{\gamma}$-ray decay of the ${J}^{\ensuremath{\pi}}={0}^{+}$ shape isomer at 2557.6 keV of excitation in $^{238}\mathrm{U}$ has been reinvestigated using the $^{238}\mathrm{U}(\mathrm{d},\mathrm{p}\mathrm{n})^{238}\mathrm{U}^{m}$ reaction with a new two-detector technique. A line at 2512.7\ifmmode\pm\else\textpm\fi{}0.5 and another possible one at 1877.6 keV are attributed to decay of the isomer. The cross section for production of the 2512.7-keV $\ensuremath{\gamma}$ ray by 18-MeV deuteron bombardment of $^{238}\mathrm{U}$ is 42\ifmmode\pm\else\textpm\fi{}12 \ensuremath{\mu}b, consistent with our earlier conversion-electron work on $^{238}\mathrm{U}^{m}$. The isomer decay is about 5% by fission and 95% by $\ensuremath{\gamma}$ rays and conversion electrons.