Ford use what is referred to as a 5 x7, commonly replacement speakers are called 5x7 or 6x8 and will work for your application provided the depthe of the speaker does not exceed about 3.2".
Door Speakers are 6x8...
6x8 door speakers
The 2003 Ford Expedition has a V8 engine.
6x8
The 2003 Ford Expedition has a 4.6 L base engine size.
Front and rear speakers are 6" X 8".
All 4 doors speakers on the Ford Expedition are 6x8.
6x8
I don't know what size speakers are in the Tahoe. But the Speakers in the Ford Expedition are 6x8 on all the doors. If the sizes are the same they will fit.
On a 2003 Ford Expedition : 106 liters ( 28 U.S. gallons )
6X8 inch speakers for front and rear doors.
6 by 8 but not to much of a choice in that size tho