Looking for info. on checking fluid level. Also I haven't found manuals yet, let me know if you have a set to part with.
I have two of the 2221-1 allison trannys. If there is no dipstick there is more than likely two plugs on the engine side, left of the transmission. One plug is maybe an inch and a half higher than the other. When the transmission is warm and idling in neutral, take out that top plug and fill until it just starts to come out the top hole.
Thanks, found two petcocks where described. Looks like they may have been added to make checking easier.