older 6x4 trans-axel fluid

I have an older 6x4 - and I don't see any way to drain the trans-axle. I am reasonably sure that this machine has not been well cared for based on the condition when I purchased it.

The brakes which are an internal part of the trans-axle - are very noisy - squeeky. I found a suggestion to check refresh the oil. The oil is at the proper level on the dip stick...

Do I need to drain this oil - is there a drain plug or do I need to suction the oil out.

Thanks
-J-