WTB: 3.90 R160 Preferably a VLSD

[rjburner]

As the title states I'm looking for a 3.90 rear diff for a 6mt swap into my 2005 WRX.

[mike-tracy]

You probably know this but the wrx's transmission uses 3.9:1.1 rear differential, which isn't the same as 3.90:1 as 1st gen turbo legacys use.

Does your 6mt have a 3.9 final drive? If so then you should do a google search on how to convert your wrx's (assuming it's 3.9:1.1) rear differential to 3.9:1 - you can use an open 3.9 to get the parts you need.

Personally I think using almost 20 year old diffs in a newer car is asking for trouble. If you use the older vlsd from the legacys, you'll need to convert the rear diff to accept male axle stubs.

Hope that helps
Mike

[rjburner]

2005 WRX's have 1.1:1 transfer gears and a 3.54:1 rear diff to come out to a 3.90 final drive. The 6mt I'm swapping in has 1:1 transfer gears and a 3.90 final drive. So as you said all I really need is the 3.90 r160 ring and pinion for the rear diff.

Subaru diff ratios change so much between models/trims/years/etc it's hard to pin down what ratio a car sitting in a salvage yard has. I just know that some legacy's had 3.90 rear diffs and was hoping there were a lot of spares floating around here. If you know a better place to find a 3.90 R&P please let me know!

Thanks
Rick

[mike-tracy]

Well you know more about the specifics of the transmissions than I do. I do know:

1991-1994 Legacy SS & Touring wagons had 3.9 rear diffs. On both autos and manuals. The non turbos had 4.xxx. Only the 1991 turbos came factory with a vlsd, so the 1992-94 open ones would be cheaper.

My old 1998 Impreza 5MT had a 3.9 rear also. I'm sure some other 1st gen 5mt Imprezas did also.

EDIT:
Here's a link with a small list for USDM cars:

http://wac.addr.com/auto/obs/lsd/lsd.html