TOUSCHE. Didnt think about the OHV vs the SOHC.. ANd my truck was better OFF road with the 4.56 but onroad it was about the same as stock.. but again totally different engines, so my argument is null lol.. my bad

Well I didn’t forget I just didn’t know that, very interesting.

FX4w… what rear end do you have ?
If you had the 28 spline axles did you upgrade to 31 spline setup ?
What is this Aussie Locker, an Air Locker or one that is put in the open diff ?
Is it worth changing to the FX4 Axle ?
What else do we need to know ?

After listening to you guys, I will be going to 4.56 gear, yes frt and rear, what are the choices for lockers and is a locker the right way to go ?
Speaking of the right way to go, is the Lock Right any good ?

FWIW… this is good information, thanks !

Ok so let me get this straight.. i have a 2008 FX4 regular.. not level 2. According to what shane said, i can only fit 4.56's is this correct or am i confused all to ****? If i can run 4.88s i will, but if i can only fit 4.56's then thats what im doing, no funds right now for new diffs..

Do you have the 31spline axle or the 28 spline axle??? This will determine what differentail is back there and will also tell you if you can or can't run 4.88's with it.

And before anyone says it......the 31spline/Torsen axle was OPTIONAL on the Fx4 Off Road model 08-09. The Level II went bye bye after the '07 model year. The standard axle on '08-09 Fx4 Off Roads is the 28spline/Trac Loc diff.





Ryan....here's some pics for ya to compare....

8.8 28spline...notice how straight the tube is...
Attachment 112912

8.8 31spline...notice towards the right how it really dips down to a smaller diameter....
Attachment 112913




And if you'd like, you can take a tape measure to your axle housing between the pumpkin and the right side spring hanger, post it up. I'll measure my 31spline to compare. That's be one way to compare and figure out what axle you've got.

thanks shane, as usual your always a good help. ill take a look tomorrow!

Even 4.56's barely work with a Torsen L/S.

So my question to you is, I was thinking 4.56 gears for 35's and carrying a camper, but after reading all this i almost want to get 4.88 gears. I need to get a gear set for my rear witch is the 31 spline 8.8 and the front is a dana 44, and it allready has 4.56 grear set in it, so would it be worth it to redo them both or just put 4.56 in the rear? and what are the hwy speeds like between to two gears?

Good info and a lot of it.
i have an axle out of a ’94 Navajo (Ex Sport), wonder if it would work with the ABS and the such, this navajo does have rear ABS.
I will have to read up on the Ex/Navajo Axle Swaps.
If i use the Navajo Axle, it is a Posi and from what I can tell a decent one and so I have been told 31 spline shafts and from what you are saying it is the way to go…
I think I saw a kit for the Leaf swap over.

The 4.56s IMHO I believe all you would need is a new Carrier not the whole Housing, i.e. Detroit Locker, Air Locker, or a aftermarket carrier for the 4.88s.
Another thing about the Detroit Locker (Auto Locker) in a Ranger with the lite ass-end, there is a question if the diff ever differentiates when turning.

Thanks Shane.

Auto lockers work fine on the street. I'm putting a Detroit in the back of my F150 even. They won't differentiate in a corner if you are heavy in the throttle, but it's hardly noticeable. People with manual transmissions don't like them as much because you are unloading/unlocking them between shifts (and because they are pussies! - j/k shane). ;)

so what are hwy speeds like between 4.56 and 4.88 with 35's?

STFU NOOB! No Fiddy parts for you!!



jkjkjk.

Believe me...you WANT 4.88's. And you wanna swap both front AND rear axles. Durr. lol.

I'm a manual w/ steel wheels and 35's w/ 4.88's.....5th gear at 80mph = 3000rpm. @ 75mph = approx 2800rpm. It's perfect. Engines at it's powerband making torque to keep the thing moving......and pulling good mpg numbers. I reguarly see 20 on road trips.

I don't remember RPM, but with 33s and 4.88s, freeways were no problem at all. The engine was in it's power band and it worked awesome. But with 33s I didn't get much over 14mpg (highway, freeway or city). With 35s (like Shane has) it will be perfect.

Ok so i definately have a 31 spline.. i have the axle that tapers in like the picture shane posted.. does this mean im capable of 4.88's?

It mean's your stuck with needing a new carrier w/ 4.88's or just gearing to 4.56's. With 35's and 4.56's, it'll feel a little slower than 33's and 4.10. For what it's worth, a Ford Racing Trac Loc LS for a 31 spline isn't much money at all ($250 or so)...it's worth it to spend a little extra in the end and have that much better gear w/ 4.88's.

My only problem with the 4.10 /33 pkg is the hy-way in 5th, hills get BIG all of a sudden, taking off in first it isn’t where is was but it is OK.
I will be going to 4.56 BUT i only have the 33 and do not intend to go bigger.

Shane,
How good is this FR Trac Loc LS setup ?
Is that the same thing that is the Ex Sport Package ?

If you have an auto transmission, you are much better off swapping in an open carrier with an aussie locker than a crappy clutch based limited slip.