Axle Swap or Gear Swap?

[shr3dd3r 09]

I have a 2000 Ranger 4x4 with 4.10 gears that I just swapped a Cummins 4BT into. It runs and drives great, but at some point I'm going to need taller gears to really be able to cruise well on the interstate. I think a 3.07 or 3.08 gear would work perfect.

Right now my rear axle is a 28 spline 8.8 open diff and the front axle is stock Dana 35 SLA standard rotation.

My options are to either swap the gears in both the front and rear with a 3.07 ratio (that looks like the tallest that is available for both front and rear).

Or... I can find a 91-94 explorer with a 3.08 ratio 31 spline 8.8 and swap that in, then swap the front to 3.07. I couldn't find aftermarket 3.08 gears for the D35 SLA.

The 31 spline is stronger I know, but I'm not planning on making much more than 130hp and 350 ft-lbs with the 4bt since I'm using an M5R2 transmission and I don't want to break it. Towing will also be minimal.

I feel like the 28 spline would hold up fine unless I was making a lot more hp and torque, but explorer 8.8s are also really easy to find for cheap. What do you all think?

 

[adsm08]

I have never seen and Explorer with 3.08 gears. They usually didn't go past 3.55.

3.08s were usually reserved for 2wd 4.0 trucks. If you genuinely want the 3.08s you cheapest route is going to be swap the whole rear axle and then rebuild the front. If you are more concerned with long-term reliability than with immediate expense I would just rebuild both ends with the gears you want and be done with it.