  We have monitored the atoll-type neutron star low-mass X-ray binary 4U
1636-53 with the Rossi X-Ray Timing Explorer (RXTE) for more than 1.5 years.
Our campaign consisted of short (~2 ks) pointings separated by two days,
regularly monitoring the spectral and timing properties of the source. During
the campaign we observed a clear long-term oscillation with a period of ~30-40
days, already seen in the light curves from the RXTE All-Sky Monitor, which
corresponded to regular transitions between the hard (island) and soft (banana)
states. We detected kHz QPOs in about a third of the observations, most of
which were in the soft (banana) state. The distribution of the frequencies of
the peak identified as the lower kHz QPO is found to be different from that
previously observed in an independent data set. This suggests that the kHz QPOs
in the system shows no intrinsically preferred frequency.
