I am currently restoring an Oliver H.G. .42&amp;quot; crawler tractor (ser No 30GA300, Eng 1 x K-3 1298493)  I am seeking information regarding the proper way tro remove the engine from the main &amp;quot;chassis&amp;quot;.  I do not have any appropriate literature to refer to.  Visual inspection seem&#039;s to suggest that the bell housing assembly had to stay in place on the chassis?  I would be very grateful if somebody could give some clues?