What rear end do I have?

[SScott]

I have been lurking all morning and I "think" I found the answer but just want to be sure.

I have a 94 Explorer 4.0 auto 4x4. Do I have an 8.8 with 31 spline axles?

I have big tires and the 4.0 just isn't working out driving daily since I am used to driving a supercharged mustang so I want to do a gear swap but need to know what to look for.

Thank you kindly,

Scott

 

[ZTraz77]

yep u have just that..you can also look at the tag on the rear differential to see which gear ratio u currrently have and if its an open or limited slip diff

 

[SScott]

Thanks ZTraz!

When I bought it I was told he put 3:73's in it but it feels like 2:73's! I know the front has a locker and pulls hard so maybe he just put them in that? I can't even use overdrive, it is useless. It drops to about 1200 at interstate speeds so I just use 3rd everywhere.

I hope to find a 31 carrier with gears already in 4:10 or 4:88 on eBay or forums at a good price.

 

[Maniak]

You are going to change the gears on both the front and rear axles at the same time, right? Just making sure since it didn't seem like you said/implied that and you must if you want to use 4x4 at all.

~Mark

 

[SScott]

Mark, I planned on following up at a later time to do the front to match. Would it hurt to use the front until I make the swap?

Maybe in need to go through the pain of seeing what is in the front... I know the sticker says 3:27 but it has been separated and has orange silicon everywhere and the original owner told me he put 3:73's in but it really does not feel like 3:73's at all in the rear.

 

[Maniak]

Yes, you need to change both otherwise you will get extreme drive line windup and will end up breaking things quite fast. Basically the front and rear drive shafts are locked together when your in 4x4 and if the front tires are trying to turn 1 speed and the rears another speed something has to give.

You can check the gear ratio by locking the hubs (I'm assuming you have a manual hub) and spinning the tire.

The drive shaft should spin 3 3/4 times for 1 rotation of the tire if you have a 3.73:1 in there.

If you don't have manual hubs you can do the same test by turning a front axle shaft and counting the driveshaft spins but you won't get near as much leverage and its hard to get your hand in there to turn the axle shaft.

~Mark

 

[SScott]

Well that is a plethora of information, thank you sir! I will check this weekend using that method. I know when I am off-road the front pulls hard and turning is very hard and it jumps, I assumed it was a locker but it could already be mismatched judging by what you said.

 

[Jason94sport]

What size tires?

 

[SScott]

33x11.5x15 on stock narrow wheels. There are as tall as the 35 11 boggers I had in the pic.