The problem is that the 5 speed camplate needs more rotational travel. On mine it seems by about another 9/16 of an inch. What i would do is still run the G53 bevel stop, but on the G39 AS bevel gear, i would grind some extra travel to equal sides of the cut out area on the bevel gear to give you the extra travel, say around 2 mm per side, and try it out. Ideally it would be nice if the G39 AS bevel gear had two more teeth on it, because when the 5 speed is used, this gear is more or less at its extremes.....that is that in either 1st or 5th gears, the bevel gear is only engaged by about one tooth, although i don't think this presents any issues. Do a dummy fit up of the gearbox and rotate the G40 shaft through its total travel making sure it engages all gears and neutral...then double check it is fully engaging 1st and 5th gears by selecting either one at a time and unscrew the G37 cap nut, remove the plunger/ spring assembly, and check that you can visually see the detent in the cam plate for that gear, and is fully lined up with the center of the hole. This check is to confirm that these gears are in fact fully engaged and that the detent plunger is holding it in gear.....this is why you need more travel with the bevel gear.......Hope this helps......Greg.