Diff center identification

dv8one · Postby **dv8one** » Fri Mar 07, 2014 12:10 pm

I have this diff center that I assume is from a auto It has 4.1 gears and a torsen center.

The number on the center is 4030-9402008 but I can't find any info relating to it, is it even mazda?

What I would like opinions on is should I keep this center or replace it with a helicoil center that I have? I'm assuming its not worth it.

Thanks

hks_kansei · Postby **hks_kansei** » Fri Mar 07, 2014 12:50 pm

What model is it from? NA/NB
1.6 or 1.8?
Aussie model? Jap model?

Any pics of the centre? should be pretty obvious if it's a Torsen from looking at the centre.

If it's the original diff for an auto, it will be an open diff. (and I'm guessing since it's a 4.1 it should be an NB8A)

Regardless, a pic of the diff centre will make ID much simpler

dv8one · Postby **dv8one** » Fri Mar 07, 2014 2:38 pm

I don't know what is from just a random diff I took a gamble on from eBay.

Just curious if it's a Mazda centre or not really?

Thanks

hks_kansei · Postby **hks_kansei** » Fri Mar 07, 2014 4:19 pm

Certainly looks to be an LSD of some sort to me.

Which would suggest it's likely from a 1.8 NA, or an NB (that's a good thing, the 1.8 diff has a larger Crown wheel and is stronger)

The lack of visible helical gears suggest it's not a T1 Torsen

That only leaves:

T2 Torsen (Mazda OEM/option)
Clutch Pack (Aftermarket)
Viscous (which would mean it's from a 1.6, and therefore the smaller diff)

Unfortunately it's hard to tell 100% from pics, and you don't really want to open the diff up to look inside (you need the proper equipment to correctly set the lash when reassembling, otherwise you risk the gears chewing each other up)

You can narrow it down a bit more by measuring the crown wheel diameter, 6inch means it's from a 1.6 NA, 7 inch means a 1.8 NA, or an NB.

Viscous diffs only came in 1.6 NAs if I remember correctly.

Out of those, the one you want is the 7 inch diff with the Torsen Type2 (unless you want to drift, then the clutch pack one is a better choice)

The 1.8 diff is the stronger of the two options, and the T2 is the stronger of the two Torsens.

Locutus · Postby **Locutus** » Fri Mar 07, 2014 4:42 pm

That is a genuine Mazda Torsen T2 out of a 1.8.

dv8one · Postby **dv8one** » Fri Mar 07, 2014 5:06 pm

Locutus wrote:That is a genuine Mazda Torsen T2 out of a 1.8.

That's what I thought just from the external appearance.

Still surprised there is no information on that part number online.

Thanks for all your input guys.