In this thread we will discuss 28 to 31 spline conversions

94m5

94m5

Dmaup's Daddy
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ok, long story short is,


I bought an Explorer diff, and just now learned that it is a 31 spline. Jeremi said that there isn't much difference length wise between the cobra cv shafts and the viii units.


My question is, has anyone put cobra halfshafts in a viii? I can buy new shafts fairly cheap and would like to go this way. I have heard there is only ~3/8" difference between the two.

If not, I'll just put the new inner knuckles on my old shafts. I would like to have 100% new shafts, but can deal with rebuilds.


Sorry for all the questions lately, I'm just trying to get things lined up in advance.



Mike
 
I have no clue what we are talking about :) But Mark VIII new OEM shafts can be had for $100 on eBay right now.
 
the side gears and hubs will have to be change or use a 99 and up IRS diff. when it comes down to it

31= stronger
28-inexspensive
 
It is a 02 explorer center section. Is there any way that I can use the stock side gears in the new diff, or should I sack up and pay the 215$ for a new diff from Max?

Thanks guys

Mike
 
Its alot of work for used side gears. you can get a center section for less then that. I would say just buy one and put it in.
 
you mention, putting the inner joint on the existing axle (in one way or another) could be a possibility
 
I am working on changing to 31 spline at the moment finding axles for a good price is my problem
 
Allright guys,


I think I'm just gonna break down and buy the new Diff from Max. For 215 Bucks, it's not worth my time and aggrivation to tear apart a brand new set of CV's and Frankenstien ones that will work.


If anything, I'll throw a quick rebuild on my 31 Spline diff and E-bay the sonofabitch.



Thanks for your insight guys.


Mike
 
94m5 said:
I must have missed this before, Will this work? I figured there would be a difference between the open spiders and the trak-lok units.


I'll gladly go this way if it will work.
Click to expand...

there is a difference between open diff and track-lok diff. Spider gears don't have much to do with the open or track-lok If you got an open diff you can change side gears to make it 28 or 31 spline if you need. I also thought that an explorer diff had only one mounting spot on the front of the diff or did you by just a track-lok If it is just a track-Loc and It is the same as a f-150 or cobra 03-04 you can not change the side gears to 28 spline you would need 31 spline half shafts new at for the retail for $276 each pending on your discount
 
Just as an fyi, 99 Cobras are 28 spline. 2001 and up Cobras are 31 spline. Also, 28 spline gears are physically smaller than 31 spline gears, so they won't work.
 
ok, I'm a bit confused,


I have a complete 02 explored center section. I want to pull the trak- Lok out of it, and pull my original 28 spline spider gears out of my open differential and put them in the explorer differential to make it a 28 spline in stead of a 31.

Will my original 28 spline open differential spidergears work in a limited slip setup?


Thanks guys

Mike
 
hope this helps on the right is a 03-04 cobra track-lok 31 spline side gear and pinion shaft on the left is a open diff 28 spline side gear and pinion shaft

side gears.JPG


pinion shaft.JPG
 
95sc said:
That's incorrect, 00 cobra R and 01 cobra had 31 spline differential also.
Click to expand...

sorry you are correct forgot about that one not a very commen rear end to show up for sale and I was talking about cars not trucks so dont go there
 
BTW swapping to stock 31 spline axles won't make your IRS stronger because they still use 28 spline outer shafts and that's the spot when axles brake most of the time , anyway .There is a guy over on Tccoa running DSS cobra level 5's
 
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