Rear Axle upgrade.

[Spiky]

I have a 1998 (that I bought new) 4x4 XLT Supercab. Ive put 345,00 on it and am just 5k into a reman. I know there was a model of Ranger (FX package maybe?) that had a 31 Spline 8.8. Is there a way to upgrade one that has the 1" axles and the 28 spline , or do I need to replace the entire rear axle assembly with a narrowed one from an F-150 (as Im sure I wont get lucky enough to find one that actually came from another ranger? Or does somebody make an aftermarket unit that you dont need a second mortgage for? Im currently working on rebuilding my original 4.0. Ive ported and matched a set of aftermarket heads. And I have one of those high lift (1.8:1) roller rocker setups from Tom Morana, plus some forged flat tops that should make 10:1 depending on my head gasket. Thank you

 

[RonD]

What's the concern with your current 8.8" 28-spline rear axle?
Its 1.2" diameter
31-spline was 1.3"

What size tires are you running now?

Good place to look for Ranger info is here: https://www.therangerstation.com/tech/

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Loads of "been there done that" info

The 2002 FX4 and then 2003 - 2007 FX4 Level II had the 31-spline axles Torsen Limited Slip

 

[rubydist]

The 31 spline Ranger axle is pretty hard to find. They were only on 2002 FX4, 2003-2007 FX4 Level II, and optional on 2008-2009 FX4 trucks. You would have to swap the entire rear axle assembly. An Explorer rear axle swap would be much less work than a F-150 axle swap, and the Explorer axles are still reasonably easy to acquire. I agree with Ron, you likely don't need 31 spline axles.

 

[SenorNoob]

28 spline axle get ran in drag Mustangs all the time. Only reason I swapped the 8.8 in was it was cheap, relatively easy, and I wanted that style of disc brake.