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Discussion Starter #1
I'm ready to start building my 9".

I have it apart, and the axcles are 28 spline. I ran into a guy that has a 3rd member for sale 3.50 gearing and a trac lock. He only wants $250 for it and says it's in great shape. thing is it's a 31 spline.

here's some of my questions,
--- should I look for some new axcles to fit this 3rd member?

--- If I stick with these axcles and look for a 3rd member with track lock, 28 spline, and the gearing I want, will I have a problem with it fitting?

the 9" was made for quite a few years, and the housing of the 3rd members look different, are they interchangeable?

the gearing I have now is 3.25:1, should I just order a locker from summit ($400) and put it back together?

Here in San Diego we have an auto swap once a month, then on the week end of the 23rd, we have the "Big 3" which is huge (fills up Qualcom stadium parking lot), I might be able to find what I need, but you never know what you'll get at the swap.

I've seen some of the links that have been posted on this topic, but if you can answer these questions it would help allot.

Thanks,

-------------------------------------
'56 f-100
'72 gran torino clip
351C .030 over 4v
holly 750,on top of performer (switching soon)
built c6
soon to be built 9"
 

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As long as the the 3rd member is from a 9 inch, it will be interchangeable. Some look a little bit different on the outside (honeycombs here and there, etc). To be safe, just take your old gasket to the rear end and see of it lines up with the bolt pattern. But, some came with different sized wheel bearings so if you have to swap out for 31 axles be prepared that you may have to spend aditional money on bearings and to have correct ones pressed on.

If I was in your position, I'd probably take the $250 rear end with the 31 spline axles. You will have to buy new axles (about $100 each) and possibly replace the wheel bearings (about $25 each plus installation), the 31 splines are stronger.

Of course, this is all coming from the guy who had a 28 spline detroit locker, and snapped the axle right as it went into the locker and it bent out my locker. Damn that sucked...I'm now a big fan of the 31 spline.

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<font size=-1>[ This Message was edited by: Wildcat on 2/13/02 12:25am ]</font>
 

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Discussion Starter #3
so, is this one of those cases whare bigger is better?

I was wanting to go with the thicker 31 spline. I do beleive they come in various lengths.
--are the housings the same whare the bearing hits the seal?
--what about lug bolt pattern, or is this even an issue? (all the same)
I don't want to open up a can of worms, if I don't have to.

thanks for the info Wildcat
 

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It's my understanding that the actual thrid member (the carrier) is the same in all nine inches. Of course yolks may vary. The only other thing that varies is the spline count.

There are 28 and 31 inch spline axles and yes they come in many different lengths. You will see that changing axles can be complicated and may be "opening a can of worms", here a are few links you might find helpful. (They were provided on a previous psot by "Just Strokin" ).

http://www.woodyg.com/fairlane/finfo/fordrears.html

http://www.geocities.com/kevinstang66/Ninecase.htm

I'm pretty sure housing sizes (where the bearing presses in next to the inner oil seal can vary also. I know the older broncos had "large bearing" and "small bearing" variations. I'm not sure if these were increases in the size of the inner bearing (against the axle), outer diameter of the bearing (axle housing). But I know they had different wheel bearing part #'s.

As far as lug nut #'s, I think they all had the same five lug ford bolt pattern (this is the same 5-lug jeep pattern but different from the ch*vy 5 lug). But if you see an axle with more than 5 lugs, I'd avoid it.

Having hear you say you do mot want to open a can of worms, I'd definitely stick with your 28 spline axle set-up. Even if you have to pay $400 vs $250. You will spend at least an extra $150 trying to make the 31 spline conversion and it will be a lot of time and work as well. And the benefits of the 31 spline axle are minimal.

I had a bad experience with the 28 spline but this was in my truck and it saw a lot of fairly hard off-roading and this is very hard on drivetrain components. I blew the nine inch out of it yearly (I have broken a ring gear, blown up a posi unit, snapped an axle which killed my locker...). Most people who have 9 inches in moderately built cars say they have minimal trouble with the 28 spline so i'd be safe and save yourself the trouble and go with the new locker.

You can install it yourself or pay someone about 50 bucks to do it if you pull the carrier out and give it to them.



<font size=-1>[ This Message was edited by: Wildcat on 2/13/02 6:48am ]</font>
 

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Discussion Starter #5
there are to many options with out knowing all the variations, so..........

I'll spin my wheels and grind my gears (think about it).

I like the idea of "NEW" but if I find a third member with 3.50 gearing w/ a locker and the 28 spline for as good a price with out looking all over hells half acre then we'll see.

**does this sound like to much to look for?**
 

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If your not in a hurry I'm sure you could find a 9 inch with what you are looking for. Make sure the there is not too much gear backlash and you sould be fine (turn the yolk one way until the gears turn, then back the other way, and measure the "slop" in between. A little is okay, a lot should raise question.
 

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Discussion Starter #7
thanks again, I'm starting to think hard on this and I might just buy a new locker from Summit. Those links had some good info, I've seen both before, but the one from kevinsstang66 was a bit long so I didn't read it before, well I did this time and got a ton of info. To many ways to mix and miss match = big head ache.........

besides when buying used, you never know how hard it's been driven. My 3.50 gearing will be good seeing how it is a daily driver, and I have the hp to turn the wheels.

thanks again Wildcat
 

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I noticed the full size trucks had a bigger
diameter bolt pattern than the cars did.

sounds to me like the Lockers get destroyed
everytime an axle breaks,

I too, had 28 spliners in my car and it also
took out the locker and the bearing near it.
Happened during a launch.

$1000 bucks later and I had 31 spline Mosers
and a new Locker and new bearings all the way.

<font size=-1>[ This Message was edited by: tbird on 2/15/02 8:53am ]</font>
 

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You might try going to a rear end specialist and asking if the side gears can be changed to work with your 28 spline axles. I've changed many the other way. the side gears interchange, BUT sometimes I have to bore the halves for axle clearance
 

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sounds to me like the Lockers get destroyed
everytime an axle breaks,

<font size=-1>[ This Message was edited by: tbird on 2/15/02 8:53am ]</font>
For the record: The axle that snapped that took out my locker broke on launch too. I guess thats what I get for dropping the clutch at 4 grand on dry pavement with 32 inch tires.
 
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