I think you have removed the pin at the front top or the box to maybe top up transmission . If so the detent spring has pushed the linkage inside the box and when replaced has misaligned the manual valve. Remove front cover (30 tx) look to top left to see if a peg on the quadrant is located in the end slot of the manual valve. This valve runs horizontally across the valve block. Remove the pin again to locate peg in correct position. DO NOT UNDO THE DETENT SPRING. The spring locates the quadrant in the correct place, setting tool required. wrong location WILL cause faults.
mags
October 2009