i did some searching and also have posted in the transmission forum however i need a quick answer so i thought i would ask here as well....

i have a 6 speed swap in my 2002 wrx and blew out the rear diff...

i did the swap the cheap way and used an r160 carrier with 3.9 r&p

i need to get the car back on the road asap because its my daily

what i need to know is if 94 legacy rear splines are the same as wrx rear splines.....

thank you

andrew

the rear carrier no, you need to transfer over the carrier section out of your WRX. It has a much stronger spider gear set then the legacy differential. Otherwise the cases are more or less identical


i guess i should ask what you broke first

im pretty sure its the spider gears......

andrew

im pretty sure its the spider gears......

andrew
if that's the case then....you should find a nother WRX rear diff. THe legacy one definitely won't work. Supposedly the WRX rear diff doesn;t work with an RS but we put one in DoctorNick's car just fine.

Any 3.9 rear diff will work. If you get one from a 1994 legacy, you need the axles to go along with it. On your WRX, the stub shafts are built onto the end of your rear axles, but on the 1990-1994 legacy's, they're inside the diff, and the axles are held on with roll pins like your stock WRX front axles. The only other things you might need to change would be the driveshaft flange and possibly the two rear studs

jared's school on rear diff splines:

there are 5 setups
on the diff side:
22 splines - early diffs and non LDS diffs .. usualy identifyable by single large flower looking nut on side of diff assembly
25 splines - early jdm LSDs -identifiable by plate and 5 bolts on side of diff - axels have 2 differnt splines clicky for example (http://i24.photobucket.com/albums/c19/Scobaru/100_5343.jpg)
25 splines - later diffs and LSDs -identifiable by plate and 5 bolts on side of diff
outtie - has a male spline setup on diff (unknown count)
R180 - no idea never seen one

here is where it gets tough
axel lengths changed some where around 2000
in an older GC for example the the drive line is centered in the car. due to one side of the diff beig bigger the passenger side axel is longer (driver shorter)
in the new cars say a gda or 2000+ legacy the diff is off-center and the axels are the same length

the difficult thing is to find a set of unequil length 25 spline axels i found a set on a 98 forester w/ lsd

the open 25 spline spider gears are much bigger than the 22 spline opens ..

Any 3.9 rear diff will work. If you get one from a 1994 legacy, you need the axles to go along with it. On your WRX, the stub shafts are built onto the end of your rear axles, but on the 1990-1994 legacy's, they're inside the diff, and the axles are held on with roll pins like your stock WRX front axles. The only other things you might need to change would be the driveshaft flange and possibly the two rear studs
On the 90-94 Legacys, the stubs can be removed and the 25 spline Impreza axle fits right in. Are the WRX axles the same as the 25 spline Impreza?

length wise .. they are equil length so unless you change the rear subframe one will be too long ..

that said if you need a set i have a set of outtie axels ill sell

-j

i think i have this resolved

someone local to me has a diff

all i have to do is have my 3.90 r&p swapped in

andrew

be sure to inspect the r&P teeth for damage chunks of spider gears do bad things..

thanks for the advice jaxx

andrew