Ford sells the 3.31 rear as Standard equipment on ALL Non-EL models. For an added $75 you can get the 3.73 rear (option only).

The 3.73 is standard on ALL EL models.

Only the 3.31 rear (with HD Tow package) will give you 9,200 max towing (4x2 or 4x4).

The 3.73 (with HD Tow package) only rates at 9,050 on (non-EL) models.

with Tow package 9,000 (4x2 EL)

with Tow package 8,750 (4x4 EL)

without Tow package ALL 2008 Expeditions Only have a Max Tow of 6,000