satoh bull s630 Transmission/Hydraulic fluid level

[flatiron]

I have a s630 diesel (2 cylinder-2 wheel drive unit).
On the right side of the transmission and immediately above where the 4 bolt hydraulic screen is, there is a plug about 3-4 inches above the screen house. What is this plug for, other than to drain the oil????
Near the top of the transmission on the right side is a brass plug, about 2 inches below the top.
What is this plug for???
In my service manual it states the transmission holds appr 3.17 gallons, in addition to this it also states the hydraulic fluid is the same as the transmission! Does this mean that a total of 6.34 gallons is required or does it mean a combined total of 3.17 gallons---Now the next question which plug is used to identify when the transmission is full (overflow), the one above the screen housing or the brass plug about 1-2 inches from the top of the transmission???
I put over 3 and one half gallons of fluid in the top of the transmission and I cannot see the fluid level. What's Up!
Thanks for any help and or advice.

 

[BillRodgers]

3.17 gallons is the correct amount. The system is a shared system. The trans is lubicated by the same oil that operates the hydraulic system. The level plug is the plug above the plate that covers the filter. This plug is about on a level with the differential lock pedal. Bill - satohparts.com 800-609-5110