How do I find out whether I have a 8.8 or a 9 rear axle? And is the front axle for a 4x4 the same as the rear or if not, how do I find that out as well? If I want to swap from a 3.55 to a 4.10, what parts will I need? Thanks in advance for any info.

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1997 Ford F-150 XLT 4x4 extended cab short bed
Options: Off Road package, Towing package, 4.6L V8, Captain's chairs, LS rear axle, green with two tone tan
Modifications: Westin Brushguard
Pioneer Premier cassette receiver with 6-disc CD changer
LT265/70/17 (32")Goodyear Wrangler AT/S
3" Performance Accesories Body Lift
Future mods: Superchip
Nerf bars(Manik)
Spray-in-bedliner(Line-X)
KC Daylighters
Winch(Ramsey or Warn)with hidden mount
Trailmaster 4" Lift Kit
35" BFGoodrich tires
16X8 or 16.5X9.75 Wheels
Dual exhaust(Ravin or Flowmaster)
Next Generation K&N II FIPK Kit
Custom hood with air intake
Seat covers(water proof)

 

Probably 8.8 inch. Check the tag on the rear diff cover. You should see 8.8 coded in, also the axle ratio.
Front diff on the old trucks was a Dana 44, don't know who builds the new axles. Should be a tag on it, maybe on back of axle tube on the passenger side.