Anyone change the rear gears?

[NASCAR Mike]

I am looking to give my 2008 Expy with 5.4l engine a little more pep. I was thinking about swapping the 3.31 gears to 3.73.

I would also get a tuner for the speedometer change and also to increase timing and firmer transmission shift points.

Anyone else do this? Are the gears the same as the 8.8 gears in the Mustang or because it has the independent suspension they are different?

 

[AllBoostNoEco]

Wow, can’t believe they used the 8.8 in the rear in the 2008 behind the 5.4.

According to Randy’s, it uses standard gears, traction devices, and installation kits.

https://www.ringpinion.com/DiffWizard.aspx

 

[NASCAR Mike]

The ringpinion.com website shows Ford 8.8" IRS SUV and Ford 9.75" IRS for my 2008 model Expedition.

What size do I have?

 

[JExpedition07]

All the rear gear sets are the same from 03-17 they still offer an 8.8” rear. Mine has the 3.73 so i have no insight on a swap, I’ll go on ford and see if i can find anything.

 

[JExpedition07]

Mine is coming back as a 9.75” on ford

 

[AllBoostNoEco]

The ringpinion.com website shows Ford 8.8" IRS SUV and Ford 9.75" IRS for my 2008 model Expedition.

What size do I have?

Go under the truck and count the bolts. If there’s 10, it’s an 8.8, 12 it’s a 9.75.
Same rules apply if it’s the 9.75. Standard gears, traction devices, and installation kits work.

I imagine it’s the same as the F-150 was, 2WD could have either depending on options, and the 4WD typically has an 8.8 front/9.75 rear.