I have a 3:55 rear end and I'm sure its nothing special but I'm not too familiar with all the rear ends, what's the 3:55 good for? Towing? And all the others that are out there, if someone could kinda explain them haha thanks

 

usually came in the trucks with a tow package from my understanding. pretty common. I do believe with the offroad package you get the lsd too

 

It's a simple concept, gear ratio's will keep your engine at it's most economical as well as put enough power to the ground to pull a trailer... your 3.55 set is a great all around gear for these tricks in thier stock condition...

If you do a lot of towing with stock tires a 3.73 set might suit your needs better our even a 4.10 ratio but your fuel economy might suffer at highway speeds...

Think about a 10 speed bicycle... Shifting into 1st is like 4.56:1 (quick and peppy but you're gonna run outta stream goin at highway speeds) and in 10th is like 2.73:1 (slow off the start but will keep your RPMs down for a higher top speed), it's about preference, maybe 5th {3.55} sits you best? which gear would you choose? Get what I mean?

 

I have the tow package and my truck came with 3.31s boooo haha, those are gone now anyway

 

To the OP,
did you mean what came stock in these trucks?
If so,
3.31 highway gearing
3.55 towing
3.73 came in a f250 light duty/7700
4.10 came in a 7700 '02 and up as an option (2wd reg cab long bed)

 

3.73 came in 2002 and 2003 fx4 Supercrews

 

Nice! ^ good call! I'm always stuck in the scab box of thinkin haha

 

Ohh ok I see now thanks for all the help guys!