That you could go to Allison Transmission on line at www.allisontransmission.com
You can search for maintenance requirements here:
My Transmission Information: My Allison: Allison Transmission
Put in your serial number and it will get all sorts of interesting tid bits about your particular transmission.
In addition. I called 1-800-252-5283
1-888-666-5799 and when I got the answering machine asked for a copy of their DVD "Allison Transmission Driver Training" DVD - DV5459EN.
They sent it free of charge. It has some good information on using the Allison 3000MH transmission and how to access oil level and diagnostic codes.