Differential regear

[pelzworld]

Doing a build/4.0 swap & have the front diff off, so time to regear along with the rear. No idea what's in it (gutless), but want 3.55 or 3.73-looking for suggestions/vendors to use

 

[4x4junkie]

The ratios you mention were offered stock. This makes it easier to just go to a wrecking yard and get a whole front chunk already set up and swap it in (same for the rear, swapping the axle whole is much easier than all of the intricate work (or shop labor charge) to set up a ring & pinion gear).

You'll probably want to determine what you already have in it first though, because already having one of those ratios would make the swap moot (or you may have some other issue... tires too big, for example, which you'll need an even deeper ratio for).

 

[Curious Hound]

There are articles in the "how to tech" section of this site that will help you find out what gear ratios you have based on axle tags and/or the door jam sticker. Then there are other articles to help you figure out what ratio you need for various tire sizes.

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[RonD]

Axle how-tos here: http://www.therangerstation.com/how-to/axles/

In that section is the way to find out what you have now: http://www.therangerstation.com/how-to/axles/ford-7-5-8-8-inch-axle-tag-door-codes/

They will, of course, have the same front and rear ratio so you can usually get it from the door label or rear axle plate

Also in this section is the "Gears needed after tire change" calculator
This will be helpful to choose the correct ratio for the size of tires you want to run

Higher ratios have more low end "get up and go", i.e. 4.10
Lower ratios have more top speed, lots of torque needed, but faster top speed, i.e 3.55

If you run 31" tires then a 4.10 ratio would be the same as a 3.73 with 28" tires, so it matters

 

[scotts90ranger]

To go with that a $$ comparison is in play... gears for either axle is $200 plus install almost anywhere you go, most axles can be had for around $200 or less at junkyards so considering gear install is at least $300 an axle if you take everything to a shop already pulled (more if in a rig) swapping axles is more economical for stock ratio's, you can sell your current axles on craigslist or whatnot to make a good chunk of that back as well...

As for where to get things, back in 2010 when I did my Ranger to 5.13:1 I bought the gears from TRS as Jim has or had the same price as anywhere else...

With what everyone else is saying, tire size makes a big difference on gear choice, so let us know that and we can recommend a gear ratio better, no matter what your truck has in it now. 3.73 and 30-31" tires is reasonable, some people like that up to 33's but that's more 4.10 territory...