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Ford 9" gurus? got a question

O

offroadman83

NAXJA Forum User
Location
Edinburg Texas
So I think I have a Nine inch ford but I pulled the shafts the other day and one is longer than the other. I then noticed the housing is very slightly offset (hard to see). Are nine inch ford supposed to be this way? I was reading somewhere that this might be considered an 8-3/8 or 9-3/8 or something like that. If it is does that mean it would be a pretty sucky nine inch. This axle does have 28 spline shafts small bearing of course with stock 4.10s and limited slip. I just got 4.88s for it. What should I do. I have a 8.25 29 spline that I was going to replace with this, should I. I am running 35" bfgs and that is where it is staying.---------Kyle
 
offroadman83 said:
So I think I have a Nine inch ford but I pulled the shafts the other day and one is longer than the other. I then noticed the housing is very slightly offset (hard to see). Are nine inch ford supposed to be this way? I was reading somewhere that this might be considered an 8-3/8 or 9-3/8 or something like that. If it is does that mean it would be a pretty sucky nine inch. This axle does have 28 spline shafts small bearing of course with stock 4.10s and limited slip. I just got 4.88s for it. What should I do. I have a 8.25 29 spline that I was going to replace with this, should I. I am running 35" bfgs and that is where it is staying.---------Kyle
Click to expand...

By replacing an 8.25 with a 28 spline 9", you are gaining a bunch of ring and pinion strength, but actually losing a bit of axle strength.

It is normal to have slightly different axle lengths on all axles, and 9's are no exception. All you need to do to identify it as a 9" is measure the ring gear. Ford made an 8" axle as well that lived under Mustangs and Cougars in the mid 60's to mid 70's, and it looks similar to a 9", but a measurement of the ring gear diameter will tell the tale.

I wouldn't put $1 towards a small bearing, 28 spline 9".

CRASH
 
Don't be alarmed at the different length axle shafts. Although that's not ideal because it would mean you could not carry one spare for both sides, several 9 inches came with one side slightly longer than the other.

The pinion yoke on the 9 inch enters the "pumpkin" about 4" offset from the imaginary centerline of the "pumpkin". To have the axle shafts the same length and thus your pumpkin centered, would mean that your pinion is then offset about 4" to the passenger side. To have the pinion centered would mean that one shaft has to be longer than the other.
Ford made several vehicles both ways and every way in between.

The 28 spline is not worth the effort to be honest. Build it up to be a 31 spline and you'll be fine forever on 35" tires.

You can order custom length shafts from Moser, Currie, Strange or a bundle of other places for about $300 a pair, bearings included. Make the upgrade to 31 spline before you put any money into some kind of a TAD.
 
Will I need to replace the third member as well to have 31 spline shafts??
 
I am thinking detroit then. Well 31 spline here I come. I think I will buy a weld on truss for the 9" as well, any reccomendations. The 9" I have is not the heavy duty housing as it is from a car as it is spring under. It is also about cherokee width already but with drums. --------Kyle
 
If your upping to 31 spline axles why not go to 33 spline? My brother has been running that on his Willys with 38s and never a problem.
 
cagedxj said:
If your upping to 31 spline axles why not go to 33 spline? My brother has been running that on his Willys with 38s and never a problem.
Click to expand...

Go 40 spline or go home.

CRASH
 
40 spline for 35's? :confused1
 
cagedxj said:
If your upping to 31 spline axles why not go to 33 spline? My brother has been running that on his Willys with 38s and never a problem.
Click to expand...

Your ONLY carrier choice with 33 spline is a full spool. It's wide open on 31 spline and for 35" tires, plenty strong enough.
 
Don't forget he's probably small bearing. You should be able to do 31 spline with small bearing outers, no way you could do 33, 35 or 40.

I am pretty sure the 35 spline arb for the 9" is out now.
 
Willis said:
Don't forget he's probably small bearing. You should be able to do 31 spline with small bearing outers, no way you could do 33, 35 or 40.

I am pretty sure the 35 spline arb for the 9" is out now.
Click to expand...

There is also a Detroit for 35 spline.....

BUT none of the 35 or 40 spline stuff will fit in a factory third member. The factory third member has 3.0625" carrier bearings. To go to 35 or 40, you need a Strange (or other aftermarket) third member with 3.250" carrier bearings. This has nothing to do with the wheel bearing outers which determine a "Big bearing" or "Small bearing" axle.
Those third members typically run around $400. Add to that the pinion support assembly you'll also need for another $400 and you now have a $800 starting point before you've even bought a locker or gears.
Strange Nodular Iron Case

33 spline is the largest shaft that can be done in a factory thrid member and the only carrier option for 33 is a full spool.
 
You are correct a full spool is the only option right now for 33 spline. So if you want a locker or limited slip go with the 31 spline, but if you are interested in a spool go with the 33 spline(same price). I agree 31 spline is enough for 35s. I used to run a 10 second drag car with 29x12.5 slicks on a 9" with 31 spline axles. Never had any problems and that was on a car that hooked so hard it would pull both tires at 6500 ft track elevation.
 
C-ROK said:
This has nothing to do with the wheel bearing outers which determine a "Big bearing" or "Small bearing" axle.
Click to expand...

But, what I'm saying, is that even if he swapped carriers and went larger spline than 31, he can't use set 20 bearing or the like because of the small ends. With the 2.835" small bearing ends, and 1.5" shafts, that sure does not leave much bearing surface area. I wouldn't go over 31 splines on a small bearing housing.

Steve
 
Willis said:
But, what I'm saying, is that even if he swapped carriers and went larger spline than 31, he can't use set 20 bearing or the like because of the small ends. With the 2.835" small bearing ends, and 1.5" shafts, that sure does not leave much bearing surface area. I wouldn't go over 31 splines on a small bearing housing.

Steve
Click to expand...

I didn't mean to sound like I was disagreeing with you either Steve. You also CANNOT do 35 or 40 splines w/o a big bearing housing (and I don't know about the 33 spline but I suspect it's the same). I just wanted to clarify because people often confuse the "Big bearing" housing with the larger carrier bearings required for the 35 and 40.
 
C-ROK said:
I didn't mean to sound like I was disagreeing with you either Steve. You also CANNOT do 35 or 40 splines w/o a big bearing housing (and I don't know about the 33 spline but I suspect it's the same). I just wanted to clarify because people often confuse the "Big bearing" housing with the larger carrier bearings required for the 35 and 40.
Click to expand...

Just wanted to make sure this guy didn't read in to far and buy a Strange case only to find out his housing ends wouldn't work.

It's all good ;)
 
Go 46 spline or go home.

CRASH
 
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