SubySal

The diffs are easy. The square drive your referring to is actually a 1/2" drive ratchet or you could use a 3/8" ratchet with a 3/8" to 1/2" adapter. I did this because my torque wrench is 3/8" drive. Now unless your talking about an automatic you will have to do the tranny at the same time as the front diff because 5-speeds share the oil with the front diff. As for the rear diff it's very simple, but if you have a skid plate I'd take it off first. It makes the job so much easier. Also if it's the first change don't be alarmed if the magnet on the drain plug has all this gak attached to it as I found out it's some sort of metallic break-in additive Subaru uses. I used Redline 75W90 fluid for the rear diff. The 75W90 includes a friction modifier and is recommended for the open diff in my RS as well as the limited slip unit in the WRX's. If you have an automatic and want to use Redline check with the Tech dept. at Redline for recommendations. I'm thinking 75W90 as well, but I'm not sure. In the 5-speed/front diff 75W90NS is recommended. It contains no friction modifiers and I can say first hand it works great in my tranny/front diff. I don't recommend "cocktails" as there are no benefits IMO. Also Shockproof has less than ideal low temp qualities and the microscopic ***** put in there to prevent metal to metal contact that break down over time. I'm not sure if this damages anything, but in a racing environment I do know these fluids get serviced much more often than on a road car. Also don't forget the crush gasket for the drain plug if you have a 5-speed. Good Luck

SubySal

I had to look up your info in the service manuals as I'm not that familar with automatics. I meant the crush gasket on the 5-speed tranny drain plug. Sorry about that.

...and yes the tranny and front diff can be done independently as they do not share fluid.

As far as your front diff goes the drain plug looks like its located just in front of where the "Y" pipe comes together. It's flat and takes a TORX T-70 to remove it. The diff is filled through the dipstick hole. The dipstick will most likely have a yellow handle and is probably located on the right side just behind the engine. Pour slowly as you don't want to overfill. Its supposed to take about 1 quart, but I've found Subaru tends to overshoot on capacity so like I said take your time here. There is a crush gasket on the front diff drain plug, and the manual recommends 80W90 GL-5 gear oil. Torque on the front diff drain plug is 32.5 ft/lbs.

The tranny can be a little more complicated. If your putting the same type of fluid back in it's a simple drain and refill unless you want to change the external filter and internal strainer. You'd have to drop the pan for strainer, but it's not that difficult. If you want to go synthetic you'd have to change the filter and strainer. I would do this anyway, but that's just me. For now I'll give you the torque on the AT drain plug (18.1ft/lbs) and if you want to do the filter and strainer I can give you those instructions as well. Also the AT drain plug has a crush gasket and the tranny capacity is around 9 quarts there kind of vague about this ranging from 8.2-8.4 imp. qts to 9.8-10.1 US qts. I'd get 10 just to be safe. It's also better to change it when warm or hot as you will get more contaminants out with the fluid change especially in the diff, but beware the tranny fluid can get well over 200 degrees.

I would definitely use sealant on the rear diff plugs as it is recommended and I forgot to do this and it does seep a little out of the fill plug.

You might be asking the wrong guy about putting it off. I went full synthetic in the drive train at around 5000 miles. One last word of caution beware of oil spillage on the exhaust pipes because if you leave it there it will catch on fire or at the very least smoke profusely. Good luck

SubySal

Glad I could help, but how in the world did you get hung up on a rock?