i put 4.56 in my open diff an ya know what i for some reason can get both tires spinning...and i can see an improvement on my mpgs and i have a 31.5 inch tire....hmmmm all the things yall say you cant achieve....or shouldnt do....so o/p go for it if thats what you want im happy with what i did and i got mine installed for 250 and yes thats the kit at moes prolly the best price on the net....i may eventually get a auburn but i couldn't afford it at the time and i needed to do something as my bearings were shot....

 

I disagree there... 4.56's and a 31" tire is a VERY sweet combination....

 

You can actually get an open diff (and even the crappy stock LSD) to lock up fairly well be applying a slight amount of brake with the gas or even using a little bit of e-brake pressure.
Something that was pretty commonly done "back in the day" but somehow got lost over the years...

 

I agree with both of you. My basic rule of thumb IS 4.10s up to 33s and 4.56s for 33s and larger is perfect for a daily driver - UNLESS you tow/haul regularly or are looking for better times at the strip, then it's 4.56s or 4.88s.

 

You may not even need that! I was doing a little "experimenting" at a stop sign and put the hammer down on my newly-acquired open-diffy truck. Lit 'em both up. Sunday, accidentally while backing up the driveway, I goosed it a little and left two short little black marks again. It seems that on these trucks, when both tires have fairly equal traction, they might be inclined to spin together.

Now, with one off the road and one on, the open differential will show off its "openness". Although, I've had much looser differentials including (unfortunately) the front diffy in my Escape. It takes nothing to get a one-wheel spin out of that car, especially on a loose surface. With the truck, it seems to act a little like an LSD even though it isn't.

Strange...

 

I bought a version of this kit from Moe's http://moesperformance.com/index.php...oducts_id=9046

Only wish I had gone with 4:56 instead of 4:10's.

Good luck...