I'll be doing this tomorrow and it will soon be followed with a DIY write up with pics in this thread.
The process is not as daunting as it sounds. Its easier than doing a tranny flush. :D

Tools required,
14, 17 and 24mm socket set
Jack
Stands(if you have them, or chock opposite wheel when jacking up veh if no stands)
Rag
Drain pan
Oil delivery device and
Castrol LSX 90 need either 3-4ltrs, 1.5lts min
Time required, roughly 1.5hrs
http://i316.photobucket.com/albums/mm329/grelise1/Diff%20oil%20change/SDC12745.jpg

1. Jack the rear of the car up and place on stand(only one side is needed)
http://i316.photobucket.com/albums/mm329/grelise1/Diff%20oil%20change/SDC12737.jpg
2. Undo the bolts using the 14mm socket holding the diff stabiliser to access the filler plug.
http://i316.photobucket.com/albums/mm329/grelise1/Diff%20oil%20change/SDC12739.jpg
http://i316.photobucket.com/albums/mm329/grelise1/Diff%20oil%20change/SDC12741.jpg
3. Using the 24mm socket, undo the filler plug. You will here air escaping as there is pressure build
up. I do the filler plug first rather the drain plug, stops the pressure blowing oil out the bottom and all over you.
4. Then using the same 24 mm socket, undo the drain plug, ensuring you have the drain pan in position.
http://i316.photobucket.com/albums/mm329/grelise1/Diff%20oil%20change/SDC12742.jpg
5. Lower the car to drain as much oil out as possible. Leave for around 5-10 min
6. Jack the car back up and redo the drain plug, 35nm.
7. With your oil delivery device filled, place the tube in the filler hole and pump away till 550ml is pumped in and redo the filler nut and tighten to 35nm.
8. Replace the diff stabiliser.
9. Remove everything from under the car and lower, then raise the front to start on the transfer case.
10. Transfer case is the same as the rear in terms of changing oil, only the filler plug is 17mm, and refill with 620ml of oil.
http://i316.photobucket.com/albums/mm329/grelise1/Diff%20oil%20change/SDC12746.jpg
http://i316.photobucket.com/albums/mm329/grelise1/Diff%20oil%20change/SDC12748.jpg

Now, I have been taught to drain then fill, drive round the block, drain and fill. This to allow the new oil to churn around and get as much left over sludge so when it's drained the second time, 99% of the old stuff is gone. It's not a requirement as such, it's just how I do it.

The stuff that came out of my rear diff was an ugly green colour, and in the tranfer case, dark brown. So, it needed changing.
So, money saved, and a very easy DIY

Question... Why "3-4ltrs"??

620ml + 550mL < 1.5L

Question... Why "3-4ltrs"??

620ml + 550mL < 1.5L

Now, I have been taught to drain then fill, drive round the block, drain and fill. This to allow the new oil to churn around and get as much left over sludge so when it's drained the second time, 99% of the old stuff is gone. It's not a requirement as such, it's just how I do it.
This is why.
Yes, min of 1.5 is required.

You don't have this problem with a FWD magna :P lol

Thanks for the write-up Grelise!

Grelise, I'm impressed with how clean the underside of your car is. I thought the diff stabiliser was something for catching mud! A good write-up. I'm off to the car wash to try and remove the dried-on mud from my mud catcher.

Grelise, I'm impressed with how clean the underside of your car is. I thought the diff stabiliser was something for catching mud! A good write-up. I'm off to the car wash to try and remove the dried-on mud from my mud catcher.

Theres a detail place near where I work, and part of there all over clean is they place the car on a hoist and pressure spray under it with degreaser. Looks like it came straight from the factory after they finish. I get it done every 6 months.

Just a quick note. Mitsubishi recommend with the rear LSD that you add their LSD additive.

It is called Mitsubishi Friction Modifier for LSD Oil.
Part No. MB664682.

Its not cheap. The bottle is 100ml and cost around $40. But you only use 50ml per oil change.

May be worth adding first before you put in your new oil so you dont spill it.

Its not for the centre diff, just the REAR diff.

Just a quick note. Mitsubishi recommend with the rear LSD that you add their LSD additive.

It is called Mitsubishi Friction Modifier for LSD Oil.
Part No. MB664682.

Its not cheap. The bottle is 100ml and cost around $40. But you only use 50ml per oil change.

May be worth adding first before you put in your new oil so you dont spill it.

Its not for the centre diff, just the REAR diff.

Didn't know that, it's not mentioned in the service manual.
Well, I got heaps of oil left, I could always get some and redo the rear diff again.
Is there a theory behind adding the additive?
Centre diff is part of the tranny, so no to the transfer case also?

Sorry mate, you are right, Its just for the rear diff. NOT the transfer case.
I was told to use this by a Mitsubishi expert who spends a lot of time with Evo lancers.

Just a quick note. Mitsubishi recommend with the rear LSD that you add their LSD additive.

It is called Mitsubishi Friction Modifier for LSD Oil.
Part No. MB664682.

Its not cheap. The bottle is 100ml and cost around $40. But you only use 50ml per oil change.

May be worth adding first before you put in your new oil so you dont spill it.

Its not for the centre diff, just the REAR diff.

Just bought a bottle from my local dealer. $31 for 100ml. Going to give it a try along with the Mitsubishi Diaqueen LSD oil. Thanks for the advice about how much to use per oil change as the writing on the bottle is in Japanese.

Guys,

I'm trying to understand what is being discussed here. The service manual states:

"Hypoid gear oil API classification GL−5 or higher. Above 10 C SAE 90W. Below 10 C SAE 80W."

This is not what is normally referred to as LSD oil, just normal gear oil.

As I understand it, LSD oil has the friction modifiers removed so that the clutch packs do not slip excessively which is why normal gear oil is a 'no no' in a normal LSD. The Magna rear diff is not a normal LSD however, its a VCU, or Viscous Coupled Unit which relies on the shear strength of the oil to do its LSD thing, and not clutch packs.

I found these links discussing diffs, which may assist:
http://outbacktravelaustralia.com.au/doc/Differentials_Explained.pdf
http://en.wikipedia.org/wiki/Limited_slip_differential

As far as I can tell from the manual, we have a sealed VCU inside the diff housing, as per the wikipedia article. To test, the manual says:
"VCU LSD CHECK
1. Place the shift lever in the neutral position, and chock front wheels.
2. Release the parking brake.
3. Jack up the rear wheels, and apply rigid rack to the specified place.
4. Separate the joint on the differential carrier and propeller shaft.
5. Confirm that if one wheel is turned slowly (approx. 29 Nm of turning torque) the other wheel turns in the same direction.
6. If the other wheel turns in the opposite direction replace the VCU."

So 'Mitsubishi' recommends use of an LSD oil, that has had the friction modifiers removed, and then add an expensive friction modifier additive?

Who in this case is 'Mitsibushi'?

I have been using Mobil 70/90 SHC, a multigrade synthetic gear oil to date, 165,000 kms, in my VRX AWD with no problems. The multigrade allows for the climate here in the Snowys. I have previously confirmed with the Mobil help line that the oil I'm using is more than adequate when meeting the service manual specs quoted above.

Have I got this wrong?

Thanks
Steve

My understanding of what oil to use in the rear differential is based on my personal experience. When I bought my TJ AWD it had 162K on the clock and one of the first things I did was change the transfer case and rear diff oils. I purchased Nulon fully synthetic 75W90 gear oil for the job. A work colleague who owns a WRX suggested I'd used the wrong oil; when I rang Nulon's technical dept I was informed that the oil I'd used was for gearboxes and transaxles, it was not for use in LSD's and that I should use LSD oil. Their recommended oil for my car is SAE 90 LSD oil.

More recently, I was made aware of the Mitsubishi brand DiaQueen LSD oil by Madmagna. My understanding is that this oil is recommended for use in the Evo. I purchased this oil and the tin is labelled "DiaQueen LSD oil SAE 90". I don't know for a fact that LSD oil has the friction modifiers removed. When I read of the Mitsubishi brand additive on the forum and confirmed with my local dealer it was available and they checked with the service dept that it would be safe to use, I went ahead and purchased it.

Just bought a bottle from my local dealer. $31 for 100ml. Going to give it a try along with the Mitsubishi Diaqueen LSD oil. Thanks for the advice about how much to use per oil change as the writing on the bottle is in Japanese.

I got this info from someone who currently works at Mitsubishi and is a hard core EVO nut. He knows his stuff and knows Mitsubishi service and parts very well as this is where he works.

I guess when I said "As I understand it, LSD oil has the friction modifiers removed " I really meant that they have not been added.

The story used to be that for many non locking diffs you never changed the oil. I always liked to though. Clutch type LSDs typically need changing about 40K. This is for 2 reasons, 1, the slipping of the clutches contaminates the oil, and 2, the oil is not as good at lubricating as normal gear oil because of the need for the clutch packs to grip to work as an LSD, hence it needs refreshing to do its job.

The LSD bit in our rear and centre diffs as fully sealed VCU and its fluid does not interact with the diff gear oil.

Just confused,
Steve

Grelise how do i tell when the transfer case have had enough oil? thanks :)
never had this done on my car, when i say you doing transfer care im like what!!!! i never had mine done!!!!

It says in the manual how much, but normally it is when the oil is level or just below the fill hole. Use you little finger, don't bend it down, keep the finger straight. When the bottom of your finger has oil on it, then it's full enough

Sweet :)
It says in the manual how much, but normally it is when the oil is level or just below the fill hole. Use you little finger, don't bend it down, keep the finger straight. When the bottom of your finger has oil on it, then it's full enough

Also, the fill bottle I used also has measure marks, and how much oil is needed is also stated.

Whats the experience been like with the Diaqueen and friction modifier additive? Any difference?

?? I've got the Nulon LSD SAE90 LSD oil in my Rada for the rear diff only (conventional Nulon gear oil for transfer case). Is this correct? I'm sort of confused here. I know about the Mitsubishi Gear Oil & Friction modifier that is what Mitsu provides for these vehicles. But I was under the impression that a suitable gear oil with friction modifiers already added (ala Nulon) was fine for the rear diff.

Whats the experience been like with the Diaqueen and friction modifier additive? Any difference?

No difference mate but at least you know the right stuff is in there.