Unless you do nothing but drive on flat highway, the 3:92's will do almost as good, and much better in the city. The only way I would have gotten 3:55's was if I drove more than 80% highway.

 

Is your truck 4wd? If so don't sweat it! Even if it isn't the traction control will do more for you than a LSD will. The 3.55s are a great gear- a great compromise for highway mileage and towing!!

 

my 3:55's get real good mpg. and they do really well in the snow and rain. My dad has 3:92 and when i drive his I cant tell the diff between mine and his.

 

Yeah keep dreaming...you'll get to wonderland, he he!

 

In wet grass/snow and such there is a HUGE difference in a open diff and a liminted slip.Huge.Can't imagine a 4x4 with a open differential.Seems really stupid to equip a 4x4 with such.

 

Seriously??? Maybe for a 2wd but you missed one important detail Captain Obvious... it is a '4x4'!! Simply rotate your dial to 4h and voila! I actually think it is stupid to pay extra $$$ for a LSD when you have a 4wd.

 

The traction control does a very good job of limiting slip all by itself. I was very impressed at how well the truck did this winter - and we get a lot of snow here.

 

It makes a HUGE difference in a 4x4. I stated that also if you get in anything really serious.You must not have owned a 4x4 or really been stuck before! Lots of bitchin in the winter on other forums in snow belt states or pulling hay outa fields and such about discovering that their 4x4 did not have liminted slip and one wheel in the ditch/rut and one not.

 

Although I've heard the traction control in the 4th Gens does a VERY GOOD job, there is no substitute for a solid LSD unit. But the LSD unit that comes from the factory in these trucks is far from a solid LSD.
You often have to "assist" it into activating by applying a little brake or slightly engaging the e-brake.

As far a not needing a LSD with a 4x4, take it from someone who grew up around farms and has had a 4x4 truck or SUV or both for ALL of his adult life - a good LSD is indispensable and will outperform an open diff in almost any situation - with or without "traction control".

My truck has a very solid, dependable Auburn LSD in the rear and a good set of fairly aggressive Cepek FCIIs on it but my daily driver, a Grand Cherokee Overland, with front and rear LOCKERS will get thru stuff my truck will not, even though it has a lot less aggressive meats on it.

One very major disadvantage in an IFS truck is that you cannot do ANYTHING with the front as far as LSD or Lockers. Many a time I get in some light mud while hunting or fishing and I end up with a 3 wheel drive...

 

If you feel the need for more traction, then a real locker (detroit) is a better choice. The problem with any clutched LSD is that it is degrading everytime it enguages.

If the enguagement of a detroit bothers you then something like an ARB is a good compromise.