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DRIVING!!!
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307 Posts
Discussion Starter · #1 ·
OK guys - I <<really really>> need some help... Im just exhausted and defeated. I have a brand new ford racing 8.8 traction lok, but it came with 31 splines... FFR axles come with 28 splines- 1st problem- yep 28 doesnt fit into 31... So I called FORD and asked for help and suggestions. The tech suggested a 28 spline spider gear set change (part # 2L1Z-4215-EA) that I found on EBAY for $120 (gears are a cheaper fix than new axles to be custom made).

When the set arrived I double checked to make sure the FFR axles fit into the 28 spline spider gears- IT FITS! Great, Awesome.... BUT when I got everything in the traction lok assembly, the locking pin(dowel) that goes through the spider gears and S spring.. doesnt fit:confused:- the new dowel is too big (.8750(new ford traction lok) vs .7500(new gears dowel hole diameter))

i even tried swapping the older smaller spiders(correct dowel diameter) with the new larger gears and they dont fit in the traction lok housing...

NOW WHAT???????:mad:
 

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FFCobra Fanatic
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1,091 Posts
I did some quick research and I may be wrong. I think the traction locs are different from 28 to 31 spline. Everything I looked at mentioned changing everything not just the side gears. If I am incorrect you get a free bump. I'll keep watching this thread.
 

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DRIVING!!!
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307 Posts
Discussion Starter · #4 ·
mmmmmmm...thats a maybe... the FFR axles actually slide into the larger spider gears... the problem is the smaller spider gears... the dowel from the new traction lock is too big in diameter to fit through the 'just bought' 28 spl gear set.

gotta be a solution out there....
 

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HighTech *******
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624 Posts
the splin gears are also differant between irs and solid axles.
The IRS vs. solid axle "SIDE GEAR" problem has to do with the way the axles lock into the side gears and nothing to do with the spider gear cross pin. It can be solved with a Dremel tool in extreme budget situations.

Good luck, NAVYDUDE,

-Kyle

EDIT: I agree with thebicman, it looks like you need a new carrier to go from 31 to 28 spline axles.
AGAIN: These guys are going to tell you to just buy 31 spline axles. STICK TO YOUR BUDGET! :) You can find a 28 spline Trak-lok carrier easy, probably on this forum...
 

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ff cobra master craftsman
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2,784 Posts
Why dont you just have a set of 31 spline axles made?.
 

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FFCobra Fanatic
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1,679 Posts
I agree with Wrench87. You might want to keep the 31 spline set up with that big stroker (408) you're using. The only "expensive" things on these cars are the parts you buy and can't use! (or break later: 408 = tons on torque!!)
 

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692 Posts
The cross shaft diameters are different between the 28 spline and the 31 spline units. So, the spider gears are different between the two units also. You'll need to see if the 31 spline unit's side gears will interchange with the 28 spline pieces in your new kit. I'm not sure if they will. If you can use the 31 spline spider gars with the 28 spline traction lok parts, you'll be okay. If they don't mesh properly, I think you're SOL. You'll need to buy a 28 spline traction lok bare case.
 

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HighTech *******
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624 Posts
Is it possible to run a 31 spline inner CV plunge joint with the 28 spline tri-bearing "tripod" end? It's the only other stop gap I can think of that might be cheaper than going all out with 31 spline axles.

Kyle
 

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355 Posts
Out of curiosity why did you get a FRP Trac-Loc?

I have an Auburn posi in my IRS, fits the FFR 28 spline axles perfect. Works great too. Barks just slightly going around sharp corners at speed. When you want to it leaves two nice black stripes. Plus no infamous clutch packs to wear out.

There are also another thing to look at here. FFR half-shafts are not the strongest, if you plan on running sticky tires or beating on them hard then custom axles may be best anyways.

If you can return the Trac-Loc and the spider gear you can get a Detriot, Auburn, or other diff for not much more money and no cobbling to make it work.
 
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