Encountered a head scratcher!! For some reason my GM t5 will not allow me to shift through the gears with the slip yoke(27 spline) installed in the output shaft of the trans. with out the slip yoke installed,the shifter shifts through the gears perfectly fine. All this is being tested with the engine off and maybe 1qt of ATF in the trans. Shined a light down in the output shaft and everything looks ok. Easy to spin and no abnormal slop on the out out shaft. Any suggestions ?