This is a DIY for people who wants to know. For starters let say.

Stuff you need:

1. gear fluid pump $8 at any auto store, autozone, advance auto parts, etc... you have to have it anyways to change your transsmission fluid too. Same pump can be used for both, gearbox and differential

2. Gear oil. I'm using Mobil1, 75w-90, GL-5, in my s13 open diffential. Manual says use 80w-90, but it gets cold here during winter, so 75w-90 will be perfect for all season. Cost: $9.99 per quart. You gotta buy 2 bottles, but will use 1.5 liters or approximately 1.55 quarts. Simply use 1.5 bottles of it and you will be fine. Dont overfill!!

3. Tools, yes you gotta have tools. You only need a 1/2 inch ratchet, thats all.

4. PRICE COMPARISON: My mechanic charged me $60 for transmission oil change last year and put crappy oil, which was making noises when it was cold. really bad noises all right, you could hear that thing turning. I switched to synthetic myself for under $30. So DIY always saves you I say at least 50% with some variablity of course; mostly downwards.

See pic below:

MOBIL1 75W-90, GL-5, FRONT IMAGE

MOBIL1 75W-90, GL-5, BACK OF THE BOTTLE

HOW TO CHANGE IT??

1. DRIVE THE CAR FOR 5-6 MILES UNTIL DIFFENTIAL IS WARMED UP. BACK INTO THE GARAGE, UP IN THE JACKS AND....

2. USE 1/2 RATCHET FOR BOTH DRAIN AND FILL PLUGS, IF THEY NOT COMING LOOSE, I SUGGEST SPRAYING WD-40 OR PB BLASTER COUPLE DAYS BEFORE WHILE YOURE USING THE CAR. SO YES, TAKE THEM OUT.

3. FIRST TAKE OUT THE FILL PLUG, THEN DRAIN PLUG. IF DRAIN PLUG IS OUT FIRST, AND FILL PLUG IS STUCK, SO IS YOUR CAR.

4. MAKE SURE YOU GOT DECENT PAN UNDERNEATH, CAUSE THAT FLUID STINKS AND VERY STICKY. DRAIN IT, PUT THE DRAIN PLUG BACK ON. *Edit: put the car down from jacks, make sure its leveled so all the fluid comes out. I would jack up the front of the car to fully get rid of the fluid. OPEN THE AIR RELIEF ON YOUR OIL PAN. DONT FORGET!!! ITS THE 3RD TIME I'M FORGETTING TO DO IT, AND SMALL SPLASHES OF OIL IS ALL OVER THE CLEAN GARAGE FLOOR.

5. USE THE FLUID PUMP TO DRAW FLUID OUTTA BOTTLE AND FILL THE DIFFERENTIAL THROUGH FILL PLUG.

6. USE ONLY 1.5 LITERS, YES "LITERS" OR 1.55 BOTTLES. MAKE SURE TO PUT THE FILL PLUG BACK ON.

AND YOURE DONE.

I BELIEVE ALL OF YOU KONW HOW TO CHANGE YOUR DIFFERENTIAL FLUID, BUT JUST THOUGHT SOMEONE MIGHT NEED IT.

DRIVE SAFE.
Modified by sanioll at 3:17 PM 5/16/2005

THAT PIC ABOVE WAS TAKEN LONG TIME AGO^^

JUST MAKE SURE TO STEAM WASH THE CRAP OUT OF IT, AND CLEAN THAT DIRT THAT WAS COLLECTED. MINE IS A SHINY ALUMINIUM NOW.

quick comment, i thought the fill plug was at the 1.5 ltr mark allready.so you just fill it till it leaks out? I was always under that impression.Nice Writeup!

well unless you own/have a professional lift like mechanics do, in your garage; theres no way it is leveled when the car is on jacks. <w/governors voice:> u speak english?

so its not gonna leak if it is on jacks, since its not leveled. 1.55 quarts, yah!
Modified by sanioll at 11:25 PM 4/28/2005

HERE ARE SOME FRESH PICS FROM LAST OIL CHANGE. FINALLY PUT THEM ON PC.

ALSO, YES IT DOES LEAK OUT OF THE FILL HOLE, WHEN IT REACHES ITS LIMIT.

SO YOU SIMPLY FILL IT UNTIL IT LEAKS OUT OF IT AS YOU SEE IN THE PIC BELOW. NOTE THAT THE CAR IS NOT LEVELED, BUT IT IS STILL LEAKING OUT.

MAYBE THERE IS A BIT MORE LIQUID, BUT I WOULDN'T WORRY ABOUT IT.

Awesome write up, I just did my first change today came out well.