  We present the detection of [$3.6~\mu$m] photometric variability in two
young, L/T transition brown dwarfs, WISE J004701.06+680352.1 (W0047) and 2MASS
J2244316+204343 (2M2244) using the \textit{Spitzer Space Telescope}. We find a
period of $16.4\pm0.2~$hr and a peak-to-peak amplitude of $1.07\pm0.04\%$ for
W0047, and a period of $11\pm2~$hr and amplitude of $0.8\pm 0.2\%$ for 2M2244.
This period is significantly longer than that measured previously during a
shorter observation. {We additionally detect significant $J$-band variability
in 2M2244 using the Wide-Field Camera on UKIRT. } We determine the radial and
rotational velocities of both objects using Keck NIRSPEC data. We find a radial
velocity of $-16.0_{-0.9}^{+0.8}~$km s$^{-1}$ for 2M2244, and confirm it as a
bona fide member of the AB Doradus moving group. We find rotational velocities
of $v \sin i=9.8\pm0.3~$km s$^{-1}$and $14.3^{+1.4}_{-1.5}~$km s$^{-1}$ for
W0047 and 2M2244, respectively. With inclination angles of $85 ^{+5\circ}_{-9}$
and $76 ^{+14\circ}_{-20}$, W0047 and 2M2244 are viewed roughly equator-on.
Their remarkably similar colours, spectra and inclinations are consistent with
the possibility that viewing angle may influence atmospheric appearance. We
additionally present \textit{Spitzer} $[4.5~\mu\mathrm{m}]$ monitoring of the
young, T5.5 object SDSS111010+011613 (SDSS1110) where we detect no variability.
For periods $<18~$hr, we place an upper limit of $1.25\%$ on the peak-to-peak
variability amplitude of SDSS1110.
