Gino is correct.
Also, The fill/drain hole is located incorrectly. I wish I still had the service bulletin but, the actual measurement is to fill it till you can insert the tip of your finger and bend it at the first knuckle and touch the fluid. They designed it around a 1qt capacity. Over filling it is actually as damaging as under filling it.
You can run a Muncie on 1qt with no averse effects. It will run cooler and shift faster. The P/N for the Sta-Lube is SL24229 @ Napa. I have a lot of customers who also use Brad Penn and the only synthetic I can recommend (mostly for people who can't find the Sta-Lube) is Royal Purple's MAX GEAR in a 75w-90 or there abouts. Only the MAX GEAR though. You do not need an additive package with any of these oils.