Here we go again

code/modules/shuttle/on_move.dm

@@ -1,9 +1,12 @@
 // Shuttle on-movement //
-/atom/movable/proc/onShuttleMove(turf/T1, rotation)
-    if(rotation)
-        shuttleRotate(rotation)
-    forceMove(T1)
-    return 1
+/atom/movable/proc/onShuttleMove(turf/oldT, turf/T1, rotation)
+	var/turf/newT = get_turf(src)
+	if(newT.z != oldT.z)
+		onTransitZ(oldT.z, newT.z)
+	if(rotation)
+		shuttleRotate(rotation)
+	forceMove(T1)
+	return 1
 
 /atom/movable/lighting_overlay/onShuttleMove()
     return 0

code/modules/shuttle/shuttle.dm

@@ -501,7 +501,7 @@
 
 		//move mobile to new location
 		for(var/atom/movable/AM in T0)
-			AM.onShuttleMove(T1, rotation)
+			AM.onShuttleMove(T0, T1, rotation)
 
 		if(rotation)
 			T1.shuttleRotate(rotation)