Hi, yes the rear crank seal does have to be removed as this is bolted to the ladder frame, i cannot see from Ford pictures but the front crank pulley and chain cover housing may need removing aswell.
Not good news, never known a ladder frame to ever leak on these though!
Hi, just had confirmation from someone else that the front crank etc does not need to be removed(thanks)
As for removing the gearbox etc, no its pretty straight forward, you are supposed to renew nyloc nuts and bolts inc the clutch and flywheel bolts, this is upto you though. Also remember to drain the gearbox of fluid otherwise you will get covered in it, if you put new stuff in the spec is 75w90 semi synthetic.
You will need a new rear crank seal aswell.
If you in a position to do so it would probably be easier to drop the engine and box out of the car but that depends where your doing it really!