737-400 testflight with wing stalls before the autoslat systems operates. These flight where performed due to the fact that the wingtip (first LH and then RH) stalled before the autoslat system comes into action. After several flights and adjustments it appeared that the slat auxiliary track detent arms where out of adjustment, causing the wing to stall before the slats move from extend to full extend. The fact that the stall test was performed initially, is because this a/c had undergone a heavy D check, and company policy , together with AMM requirements, requires a testflight after such a large check. The testflights where performed in 2003.