Quote:
Originally Posted by bWRX
I am not finding this FAQ to clear up a lot of my confusion regarding the various diffs that have been supplied stock in the USDM STi.
The 2007 apparently have a Torsen in the rear, as a new thing. I've noted a few posts talking about this like its a really significantly great improvement for some reason. But according to your FAQ, 2007 is the third model year for the USDM STi to have torsens in both front and rear - the 2004s had a suretrac unit in front.
As near as I can tell, it went like this:
2004 - Suretrac front, "mechanical" rear
2005 - "Helical" front, "mechanical" rear
2006 - "Helical" front, "mechanical" rear
2007 - "Helical" front, "Torsen" rear
Now, if really, for all intents and purposes, Torsen = helical = mechanical, I'd like to hear you explain why that is, but me and a lot of guys like me are still standing around out here wondering what the tiny little differences between these various units are, or where we can go to research it ourselves. There is a lot less general info about diffs out there than there is, say, suspension or forced induction concepts.
Thanks!
Here are the part numbers for each of the diffs (front, rear, and center)
Rear Diff
38410AA080 - 2004 Rear Diff Unit
38410AA080 - 2005 Rear Diff Unit
38410AA120 - 2006 Rear Diff Unit
38410AA140 - 2007 Rear Diff Unit
NOTES: 04 and 05 are the same. I have taken an 04 Diff apart, and rest assured it is clutch pack based. 2006 had a new rear diff, as did 2007.
Front Diff
38410AA060 - 2004 Front Diff Unit
38410AA100 - 2005, 2006, 2007 Front Diff Unit
NOTES: Sure enough, the 04 US 6MT had a Suretrac front diff, as the 060 part number is also used in the Version 8 JDM 6 Speed ( C, D ). 05, 06, and 07 all have the same front diff.
Center Diff (DCCD)
38913AA160 - 2004, 2005 Center Diff Unit
38913AA190 - 2006, 2006 Center Diff Unit
NOTES: 04 and 05 has the same center DCCD unit, which was upgraded in 06. The center diff used in all cases (160 and 190) are the same as used in the JDM 6 speed of the same years. AA160 was used in C,D, and E JDM 6 speeds, and AA190 was used in F and G.