So all along I though I had the 3.73 rear end based upon the fact that I have the factory towing package. I know I have the towing package since I have the factory hitch, tranny cooler, and power steering cooler. However upon closer inspection my door sticker denotes an axle code of 19 (3.55 non-LS) and the tag on the diff says 3.55... WTF? I thought the towing package had 3.73?

 

I have a towing package equipped truck with 3.55s (for now..........) so it's not unusual.

 

Same here, FX4 with a towing package, 3.55 LS.

 

I have 05 4x4 lariat with the heavy duty tow package coolers and what nots it has 3.73ls.

 

Well that makes hardly any sense. Thanks for clarification.

 

My 07 Fx2 have the towing package and a 3,55 and I have a friend who have an 2010 FX2 towing package with a 3,55 too. We both have LS.

 

Mine has the 9.75 instead of the 8.8 ,I don't know if that makes any difference.