[ob_1jr]

the fuel filter is on the passenger's side right by the fenderliner in the back. The allison has 2 filters, one internal, one external. When you change the external, there should be a magnet on the top of the filter. As far as when the fluid and filters should be changed.

External filter - no more than 10000 miles
internal filter - upon overhaul of tranny (or when you have to take the pan off)
Fluid - it depends on your fluid and driving conditions, but every 25,000 miles for "severe" and 50,000 for normal.
Fuel filter - GM says every 15,000 miles, but I would change it more like every 10,000 or sooner. It's cheap insurance on the engine.

And by the way, welcome to the site!