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AYC Fluid change (cure those donkey noises)

49155 Views 351 Replies 133 Participants Last post by  jhfozzy
Thought this may help some people who are having AYC sqwarking and grinding noses to try and cure it themselves.

This is a bit of a simple guide for people who are not familiar with the AYC clutch bath drain and fill procedure. Also I have covered the rear diff drain in this guide too.

I have just bought an Evo 5 with the classic sqwarking and grinding from the rear diff. It was quite a bad case and would even make a fair racket at slow speed turning. If you've got this problem then have a read.

Right, first off some tools you'll need..

17mm offset ring spanner
24mm socket (on wrench obviously)
oil drain tray (or container to catch oil)
refill bottle (old toilet duck bottle works a treat)
clear hose (to attatch to refilling bottle)

Also you'll need a litre (it takes less) of AYC fluid or Mitsubishi SP-III, if the car is making nasty noises I'd get a few lires of AYC fluid as you may well need to do more than one change to get it clean. I like to drain the AYC, refill with half a litre of new and drain again just to pull that dirt out.

If you're going to change the rear diff oil too you'll need a litre of regular gear oil 75w90.

Here we go then :naughty:

First, jack the car up at the back and secure on axle stands and chock wheels etc so it's nice and safe.

Get under the car and have a look at the rear diff area to get yourself familiar with the various drain and fill holes.

Here's what you'll see.

Note that the rear diff oil drain and fill IS NOT part of the AYC fluid system, it's regular gear oil.

Again another shot, note position of AYC fill plug.. it's at the back of the diff at the top and a bit fiddly to get to, not impossible though but just get your hand up there and work out how you're going to refit the plug when the time comes.

This pic was taken looking directly up at the diff.

I always like to remove the AYC fill plug before I do the drain (just incase) Please make sure you use a decent offset ring spanner (as picture) as they can be quite tight and risking destroying it with an open ended spanner is not worth it.

Once you've succesfully removed the fill plug then remove the AYC drain plug and the AYC clutch bath fluid will come out.

While I was under there I decided to put some fresh gear oil in the diff, this is not AYC related but the diff part, seperate fluid from AYC.. normal 75w90 gear oil.

You can see the refill hole

Once you've successfully drained the AYC fluid then you're ready to refill with new. I use a toilet duck bottle with a length of clear hose for this. You need to slip the hose into the fill hole at the top and squeeze away until the AYC fluid reaches the level of the fill hole (some will start to seep out the fill hole when full)

Here you can see my bottle :D

Once refilled then it's just a case of refitting fill plugs and you're good to go. As a matter of normal servicing of the AYC fluid you will only need to do a simple drain and refill


If you have noises from the rear diff I'd advise after draining to put the drain plug back and fill with half a litre of AYC fluid again then drain it again just to try and clean it out a bit more. Also if you do this and still have a slight noise after then I'd go for another change again in a week or so. From my experience it doesn't take much for the AYC clutch part to become noisey as far as dirty fluid goes! As you can see it's nice and simple, so no excuses.

Obviously the rear diff oil is a simple refill when drained and a lot easier to get to the refill hole.
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:smthumbupIncredible! More people like this guy please!!
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Keep em coming James!!! I need your kind of idiots guide so i dont keep pestering my dad! lol P.S. I have a air/fuel gauge (not expensive cheap and nasty but more for a ball park!) it has 3 wires coming from it a red a black and a grey i assume the red is power and black earth but not sure where to put the grey! Instructions are not worth a toss as it doesnt explain ANYTHING other than weather the engine is a heated or something or another! Many thenks Jess!
Those types of AFR gauges usually have a + - and the 3rd wire goes to the signal wire on the o2 sensor. You can probably use a wire off the ecu for this if you search ECU pinout.
Thanks very much James! Im trying to get more involved as you just cant trust any garages theses days and the good ones are always just a tad to far away! (Mind you who in the right mind wants to be in Blackpool anyway!)
If the af gauge tells me my car is running rich what does that mean?
Hi James! Sorry to be a pest but ive been told the ayc refill is the bottle in my boot! (EvoV) is that correct?
Why the dirty rotten f..... Thanks a lot guy's!!! I had my car in for an ayc bleed and diff oil change and the job wasnt done properly as it moan's and groans worse now! James why arent you a millionare already?:smthumbup Unless of course you already are! :lol:
And while im here my main prob is that my car is realativley fresh from japland and i've just had the clutch replaced with an exedy standard plate and exedy racing cover for extra grip (dunno if thats true!) but when it came over the guy at the ayc bleed garage saw the rear suspention and said it was very expensive HKS something or another! When i bought the car off the importer he was pretty honest and said he noticed it when he got the car and was gonna take em all off and sell em separate on ebay but he said he took the front off and they were goosed so he left the back ones on and gave me the standard ones to put back on the rear! I have no idea how standard my car is etc!!!
Are you sure they didn't do both? It certainly shouldn't be 'worse' though.

This is why you need to be carefull with dealers really. If you asked for an AYC bleed then they would have changed the pump system (fluid in boot res.) as that's the only part that relates to the 'bleed'.

Also, you say you asked for a diff oil change? that would mean the gear oil in the diff.

There's a chance they didn't change the AYC clutch bath fluid and just the AYC pump fluid and diff/gear oil?

If so, that may explain the noises still.
Thats what im thinking now as it was coinkidink that he just happened to have a spare ayc pump if i needed it!:rolleyes: I think i will give her a bath! what oil do i need to ask the muppets at the likes of halfords or motorworld for please?:D
great thread
:crackup: The best! (Im sure this guy is the Stig!) :crackup:
Thanks Again! While were here i'll just make my will out to ya!:lol:
:lol::smthumbupOkey doke got the atf dexron III now ive just gotta find the time!
two things that baffle me:

How did you get all the toilet duck fluid out of the bottle

How did you get the bottle rinsed and dried before you filled it with AYC fluid


because no matter how much I squeeze and shake and spin the bottle, i cant get all the water out!
Just literally done mine and the white plastic nozzle on the toilet duck bottle pulls out with a pair of pliers! rinse flik and then i put a little atf fluid in the bottle and squeezed it out just to make sure all the water was out!:smthumbup

Mine was making the noise real bad at all speeds and now it's gone!:jump Yippeeeeee!
Where can you buy diaqueen on the net in uk?

My local mitsubishi dealer dosent use diaqueen oil, he told my that mitsubishi dosent have any own oil, that jackass...

Then he told me that when you change the ayc fluid you must leave the car to a mitsubishi dealer, because they hook up the car to a computer or something, is that right?

And does it looks the same where you fill and drain the ayc on a evo 4 gsr that i does on the pictures who shows in here.?
An A-Typical dealer trying to rip off another member of the public!!! The dim wit was talkin bout ur AYC fluid bleed! That does not cure the noises from your AYC (i wouldnt be suprised if he didnt know about the bath section!) Dont ever go there again! Yes the AYC system bleed is best left to a garage with the correct kit but this thread is a simple DIY for the bath oil that even an idiot like me can do!:lol::smthumbup
If you check out the pic's on the firt page James takes you through everything you need to know and i used halfords atf fluid at £6.99 a bottle i bought 2 as i wanted to give it a good flush fist but high grade or low grade it worked! no noises at all the only moanin in my 5 is the wife! :mhihi: :crackup:
Great stuff MLR thanks for JACK!!! I just went downstairs to take the pics required for you all came back edited them for you as James did and because my membership expired i cant help fellow Evo owners!!!!
Guess im gonna have to surf for a better owners club!!!!:smthumbdo
Damn it i couldnt find a better club the only other one didnt even know what ayc stood for!:crackup:
If you want the pic's i will have to send them to Corky79 and let him post them wich may be in 5 min!:D
send them to me if you like and ill post them up?

[email protected]
:goingmad: Bill Gateas is a lovely man! lmao not
Cant send from my windows based email as i cant use my hotmail account but Techno is about to prevail me thinks!:)
Pics for Roadkill :lol:

Dont you laugh at me mofo! im not the one with a wind tunnel strapped to my roof!:crackup::D:utahere:

And this one is so you can get your bearings on where your looking!
Thanks T and thanks Corky! i know it was a pain but im skint at the mo and cant afford to pay £35 so i can help others! lol
photobucket is free :lol:
Take yer bucket fill it with hot soapy water and go wash yer car!!!!:mhihi::lol::smthumbup
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