I am rebuilding a 1977 F150 4x4 with a built up 460, 385 series, NP205 transfer case. The rear differential is currently open with 4.11 deferential. I would like to change out the gearing to 3.50 with positive traction.

My question is... I have heard somewhere that a late model 4x4 Explorer may have the gearing and Posi-traction I am looking for. Do any my fellow Ford Enthusiasts have any first hand knowledge of this possible swap? Or, am I better off rebuilding my existing 9"? Thank you for your help and advice.

 

Late model Explorers have an 8.8-inch rear end, and usually rear discs. "Posi-traction" is a GM term. Ford's version is called Traction-Lok.

The Explorer 8.8 is a popular swap for Jeep XJs and WJs because of the rear end width and the same bolt circle as the Jeeps.

Swapping one into your rig will require fabrication like relocating the leaf pads and shock brackets.

The Ford 9-inch is a tough rear axle... It's the same basic design as NASCAR racecars use. They use it because the gear carrier can be quickly swapped in as little as 10 minutes. Try that with an integral carrier like and 8.8 where it has to be set-up inside the housing. ... in this case, newer isn't necessarily better.

I'd keep the Ford 9. Remove the pumpkin and drop it off at a gear/axle shop and tell 'em what you want. A Traction-Lock is about $450 and rear gears are abut $200.... but with a 4x4, the better option is a mechanical locker (Eaton, Grizzly, etc.) or a Powertraxx or Lock-rite from Richmond Gear.

 

Drop it off at a shop to have the gears put in. If set incorrectly they will wear out extremely fast.

Other than that look into aftermarket lockers. An Aussie locker runs a few hundred and you can drop it in. A detroit is stronger and will be better suited for large(35+) tires. Nether have clutches to wear out over time. Both provide maximum traction 100% of the time.

 

thank you for your advice... well taken

 

Keep in mind with a 4x4 you'll have to re gear the front differential as well.