AYC Diff

[Jimbo]

I don't remember reading anything about this in the past, so I thought I'd throw this open to see if anybody has any info or advice.

Ever since I bought this VR4 I've been getting intermittent problems with the AYC diff making low sounding grinding/droning/graunching noises. Within in a week of getting it I had both the AYC fluid and diff gear oils changed which seemed to cure the problem for a while, but in the past few months the noise has become ever present, but far, far worse on left handers than on right handers, and ONLY when the AYC lights are on.

The old car started making a higher pitched whine last Easter and I assumed that to be the brake discs. Sure enough, once I swapped the discs over to the new car, the same noise transferred over as well. Unfortuantely there's also this much lower grinding noise on the new car that was occurring before I swapped the discs over.

I've just come back from Mitsy who've done me a free oil change on the diff as they drained it and found it to be BLACK (this is after 5000 miles). Sadly it's still not solved the problem as I get the same horrible noise when doing sharp or long constant radius left turns with power applied (just enough to get one bar, so 15-20mph is enough!)

I'm convinced that there's something wrong with the diff itself, as the AYC pump appears to be working fine. To further this assumption (and to differentiate it from the possibility of it being the drilled grooves of the brakediscs rubbing against the pads, which is what I think the higher pitched noise is), when I drive in the snow at 5mph in straight line and stab the throttle, i.e. so you get all AYC bars lit up momentarily, the same horrible low pitched grinding noise appears.

Can anybody shed any light on this, or has anybody ever experienced anything remotely similar? I'm convinced my diff is knackered.

[BraindG]

Mine does this aswell, ive got a feeling its something to do with the ayc fluid.

I used to get this groan before i changed the AYC switch, which also involved changing the fluid. For quite some time the noise was gone, and only recently has it returned..

So i dont think its something like the diff itself. Could just be an airlock?

[Nick Mann]

Which fluid was black?

[Jimbo]

It was the diff's gear oil that was found to be black and that was drained and refilled today.

Last summer I got them to change both sets of gear oil, and also the AYC fluid, so I'm somewhat bemused that it could be "black" now.

[Jimbo]

What's the AYC fluid for? Is it just for lubricating the pump, or does it have a more active involvement in the diff itself?

It was last July I had the oils all changed, and then they would have redone the AYC fluid last Novemeber when it had it's 72000 service, and today they've drained and refilled the diff gear oils again.

So in theory I've had all the different sets of fluid changed TWICE by a Ralliart mechanic in the past 8 months and only 5000 miles.....I wonder whether it could be an airlock, Barry.....hmmm, but Mitsy are supposed to use a special kind of bleeding tool to ensure this doesn't happen :thinking:

[BraindG]

im not sure tbh, all i know is I had the noise before changing my AYC switch, then it went away... now its back... all ive done in the meantime is change the diff oils..

[Nick Mann]

The only part of the AYC that can get an airlock AFAIK is the hydraulic side. But the oil that was black was the gear oil? Surely the gear oil is just that! The AYC fluid is for the hydraulic side and the clutch side. I would have thought those are the parts working harder under AYC cornering.

The black oil/airlock thing doesn't add up IMO.

[Jimbo]

Yeah I'm completely puzzled by it. I didn't see the oil myself, I just got the impression from reading the expressions on the Mitsy guys faces that the oil was looking decidedly tired, but "black" is the word they used. I must admit Nick, it does sound rather odd now you've mentioned it that they should use that word to describe a substance that's not exactly world famous for being bright or translucent!!!

Could it just be that the AYC fluid wasn't changed for a long time until I bought the car? I'm thinking maybe the clutches have been damaged in some way due to contaminated oils, and that any oil change now is too late.....does this make any sense?

[Nick Mann]

Black gear oil is worrying. I guess it depends on there definition of black. Most gear oil is a yellow-brown sort of colour when it is fresh. But what I meant was gear oil is gear oil. If the gears are turning (which they must be if the car is moving?) then the oil is working or it isn't.

My guess for the noise would be the hydraulic or the clutch fluid, but both are AYC fluid and therefore have nothing to do with your black gear oil. Maybe the gears work in different ways with the clutches engaged/disengaged so the problem is with that part of the diff? I guess we don't have enough experience between us.

Next bet would be to try Roger Rally I think. He impressed me with his knowledge of AYC - maybe he can confirm/deny options?

[Jimbo]

Yeah, good idea - I'll see if I can track him down on the MLR. I'm also going to return to Mitsy tomorrow to see what they can come up with - they seemed to be convinced that this oil change would solve the problem.

I'll post back I know more.

[BraindG]

Jimbo, out of interest, does your car judder a wee bit under acceleration?

[Roadrunner]

Pretty certain it's your AYC clutch-lubrication fluid. These are precisely the symptoms I'd expect if the fluid's knackered.

[Jimbo]

Jimbo, out of interest, does your car judder a wee bit under acceleration?

Nope, nothing like that. The car is sound save for this grinding noise that appears on left handers and in perfect sync with the AYC lights appearing....

....difficult to test this completely safely, but it appears to be a louder sound the more bars I get. When I was last on a dry track and pushing it (Snetterton) I was getting three bars and the noise actually started to sound sort of springy/clunky, if that makes any sense - I backed right off when I heard this and the noise hasn't come back since, but I've not been remotely close to 3 bars since either.

[Jimbo]

Pretty certain it's your AYC clutch-lubrication fluid. These are precisely the symptoms I'd expect if the fluid's knackered.

Yeah, that seems to be the consensus Brian.....but this fluid is documented as being changed twice in the 10 months and 5000 miles I've had the car. I say documented, because I'm now a little uncertain as to whether this was actually done....especially with the gear oil being reported as contaminated.

[Kieran]

Yeah, that seems to be the consensus Brian.....but this fluid is documented as being changed twice in the 10 months and 5000 miles I've had the car. ....

I wonder if they have just changed the AYC Hydraulic fluid and not the clutch pack fluid - it's the clutch pack fluid that gets contaminated...

[amsoil]

I'm a little troubled to hear about black oil coming out of a diff; I have heard of this but never seen it; it it was black then something is very very wrong there. If it was the auto fluid side its not too uncommon but still not good news; just make sure they put in Mitzy own ATF not Dextron 3 which doesn't make the grade and was designed for something else.

[Rally205]

Jimbo,

The noise is caused by small particles of dirt trapped between the clutch plates inside the diff. When the AYC kicks in it compresses the clutches and you get the noise. I had it on mine when I first bought it and I thought that the diff was knackered so I had it checked at Mitsy and they said it was knackered too. I bought a second hand diff and put that in.

The new diff did it too!! I had the fluids changed three times and it went away. I also found somemone to re-build my old diff. He stripped and checked it and said that there was nothing wrong with it. Bugger!

It can also be caused by using the wrong fluid ie Dexron III. This causes the clutches to slip and you get a horrible grinding noise. Just make sure that they use the right stuff and get it changed regularly.

[amsoil]

Jimbo,

The noise is caused by small particles of dirt trapped between the clutch plates inside the diff. When the AYC kicks in it compresses the clutches and you get the noise. I had it on mine when I first bought it and I thought that the diff was knackered so I had it checked at Mitsy and they said it was knackered too. I bought a second hand diff and put that in.

The new diff did it too!! I had the fluids changed three times and it went away. I also found somemone to re-build my old diff. He stripped and checked it and said that there was nothing wrong with it. Bugger!

It can also be caused by using the wrong fluid ie Dexron III. This causes the clutches to slip and you get a horrible grinding noise. Just make sure that they use the right stuff and get it changed regularly.

If you struggle to get Mitzy's own you can get the only oil thats to that spec from me as below; If you check the threads you will get the idea and there is a club discount in the members section which makes becoming a full member a good investment for those who aren't already. Also think Amsoil is cheaper than Mitzy's?

[Jimbo]

I had the fluids changed three times and it went away.

Excellent stuff Marcus, thankyou very much for that. :2thumbsup

My AYC fluid has supposedly been changed twice, so from your experence, could this mean that it just hasn't been flushed properly? Did Mitsy do the same with yours - i.e. just drain and refill it the first couple of times and then only when you found the new diff made no difference did they do a monster flush and refill?

[Jimbo]

If you struggle to get Mitzy's own you can get the only oil thats to that spec from me as below; If you check the threads you will get the idea and there is a club discount in the members section which makes becoming a full member a good investment for those who aren't already. Also think Amsoil is cheaper than Mitzy's?

Hi Don - I received 10 ltrs of ATF from you on Tuesday (and at warp speed too, I might add :) ) all ready for my gearbox flush.

Isn't the AYC fluid a different type of oil altogether though?

[Jimbo]

I wonder if they have just changed the AYC Hydraulic fluid and not the clutch pack fluid - it's the clutch pack fluid that gets contaminated...

Hi Kieran - are these two things different then? The way Mitsy explained it was that there are two places that require the gear oil to be changed in the diff, and then the 3rd place was for the AYC hydraulic fluid. Is there a 2nd seperate point that requires more AYC fluid, i.e to do the "clutchpack" fluid?

[Rally205]

Hi Don - I received 10 ltrs of ATF from you on Tuesday (and at warp speed too, I might add :) ) all ready for my gearbox flush.

Isn't the AYC fluid a different type of oil altogether though?


The AYC fluid is the same as the Amsoil ATF which is Mitsubishi spec SP3 or whatever.

The problem when I fitted the new diff was that Variava Mitsubishi used normal Dexron III to fill it. I found out and took it to another dealer who flushed it out and re-filled it with the pukka stuff. It had already contaminated the clutch plates though so it took a further 2-3 changes of fluid with a bit of driving in between each change to cure the problem.

[Jimbo]

Thanks Marcus and everyone else for all the valuable information - armed with all this info I'll see what Mitsy make of it - I might even take my Amsoil and ask them to fill it with that, it doesn't need much does it? Want to make sure I've got at least 9.5 ltrs for gearbox flush.

[BraindG]

Hmm, keep us posted, im trying to remember what oil i put in mine last? - this sounds like a solution...

[Nick Mann]

Hi Kieran - are these two things different then? The way Mitsy explained it was that there are two places that require the gear oil to be changed in the diff, and then the 3rd place was for the AYC hydraulic fluid. Is there a 2nd seperate point that requires more AYC fluid, i.e to do the "clutchpack" fluid?

This post scares me! Hopefully it is just crossed wires.

Hydraulic = ATF, reservoir in the boot.
Diff = gear oil, drain and fill on rear diff.
Clutch = ATF, drain and fill on rear diff.

So: 3 areas for oil, 2 of which are on the rear diff. BUT ONLY ONE PLACE FOR GEAR OIL!! If they are putting gear oil in the clutch system, then we may have found the problem!!

[Jimbo]

If they are putting gear oil in the clutch system, then we may have found the problem!!

No I doubt it Nick, it must be me getting my wires crossed - it was last summer when I had that particular conversation with the Ralliart mechanic and I've killed an awful lot of braincells since then.

Thanks for the clear explanation though, now I totally understand what goes where :)

[BraindG]

You had any joy with this yet? - I noticed my AYC light came on on the drive home from Plymouth lastnight.. might be linked..

[Jimbo]

No, nothing, nada :(

Mitsy are getting on my t!ts, they won't help me make a decision on it, they just keep churning out useless suggestions, and my warranty won't touch it with a bargepole.

At the moment my strategy is to follow Marcus' advice and get the clutchpack fluid changed asap....then I'm going to run it for 200-500 miles or so and get it changed again. Hopefully the first change will cure it.....but I've stressed to Mitsy that they need to properly flush and refill it. I'll know more next week when it's changed.

By the way, does yours sound REALLY loud as well? I understand exactly what Marcus means, but it still surprises me just how loud the noise can be at times......

[Jimbo]

RESULT!!!!!

WRD, Marcus, and Amsoil to the rescue :)

We changed the AYC clutch actuator fluid this afternoon and filled with fully synthetic ATF. Instant result - no more grinding and graunching noises!!

Although I was hopeful, I never in a million years thought it would be an instant remedy. Big big thanks everyone, Top-/Banana !

[amsoil]

Been said already but worth saying again ....

RESULT!

:2thumbsup

[Jimbo]

Been thinking more about this....I'm going to ring my dealership tomorrow and ask them what oil they use for the AYC clutchpack. I remember when I was there in the workshop with them last summer (repairing a burst power steering pipe) I noticed they had a big drum of somewhat standard looking ATF they used to re-fill my power steering.

I just wonder whether this stuff is Dextron III and whether they filled the diff with it? Although I'm so happy that all you guys in CVR4 have solved the problem for me in the space of 3 weeks, I'm actually feeling really quite p***ed off that Mitsubishi couldn't even identify the problem (let alone cure it) in the space of 9 months and (alledgedly / documented) two complete sets of oil changes to all three areas on the diff. They must get a whole bunch of EVO's go there for servicing as well, so it's not as if an AYC diff is alien to them??? I feel like throwing something big and heavy at them.

[Jimbo]

Been said already but worth saying again ....

RESULT!

:2thumbsup


Don, your oil is magnificent, truly magnificent. If you ever need one of those cheesy "James from Stoke-on-Trent says Amsoil...." quotes, you'll get me front and centre and my best wooden-acting! :2thumbsup

[richy rich]

james didnt you mean WRDamsoil and marcus

sorry mate.

im so glad this issue is solved for you:2thumbsup

thank you for supporting us.:2thumbsup


come on cvr4 (more work pls)

the drain on the clutchpack was so tight i needed a 3ft breaker bar to undo it.

don't think it has been touched in years.

[amsoil]

Well I'll say it then for my honoury membership

WRD Rocks

:2thumbsup :2thumbsup :2thumbsup

[richy rich]

thanks don amsoil rocks just as much

[Kieran]

Glad you got it sorted Jimbo. I can see more than ever why Amsoil has so many affiliate sites and so many people raving about it. Just as an aside, I've done nearly 1000 miles since the Amsoil went in Ariadne. The engine dipstick looks as fresh as the day it went in. Impressive, considering that several 'fully synthetic' brews were dark brown/black after only 3000 miles....

Richy..... Had a go at the AYC Hydraulic fluid yet? I think I need to change mine (noisy pump and it's starting to discolour) but I'm still being a chicken!!/pan

[richy rich]

Richy..... Had a go at the AYC Hydraulic fluid yet? I think I need to change mine (noisy pump and it's starting to discolour) but I'm still being a chicken!!/pan

not yet k but will do.

the biggest prob is having the car up in air to do it

[amsoil]

And now we have in stock a super brake etc hydraulic fluid. Made in Germany; we stock it because it possesses what we think is the best compromise in all areas ie quite high boiling point and without the aggressive corrosiveness of the pure race brake fluids, slow to take up moisture and good for 3 years! The bonus is that the price is good. (we have just done a deal and the price will be coming down to £16 for a litre when my computer lady can update the web site.
Check it out here :- http://www.performanceoilsltd.co.uk/brake_fluid.html

The usual Club Members discounts apply. So theres even more reason to become a VR4 Full Member.

[Josh2xsv]

Any NZ equivalents to this GOD-SENT AMSOIL???
I am really keen to get something that will do the job excellently for my next OIL/ATF/AYC changes - and they are pressing!

Any thoughts would be great! :2thumbsup

[amsoil]

Any NZ equivalents to this GOD-SENT AMSOIL???
I am really keen to get something that will do the job excellently for my next OIL/ATF/AYC changes - and they are pressing!

Any thoughts would be great! :2thumbsup

Checked up and 'If you are in New Zealand and would like to order AMSOIL products, please call 64-9-827-8442.'
I have no idea if thats a NZ phone number or what. If you have problems let me know. Also founf this one :-

Auckland, NZ
AMSOIL Distribution Centre
3/1 Binsted Rd.
New Lynn
Auckland, NZ
Mailing Address:
P.O. Box 15813
New Lynn
Auckland, New Zealand, 1232 Please call in advance to verify operating hours, inventories and shipping arrangements. 9-827-8442
FAX: 9-827-8802
bonnie@AMSOIL.co.nz

Regards Don

[Pizza]

Does the Clutch Pack fluid need to be changed at the same time as the AYC fluid? I know that both are ATF fluid but are the systems connected in that if i tell them to change my AYC fluid it will also change the Clutch pack fluid as well. i took my car today to my Mitsu shop because I am having this same crunching noise (only on slow left turns) and I mention changing Clutch pack fluid and they dont seem to have any clue as to what I am talking about.

They say there is only draining the AYC fluid and draining the Gearbox fluid and anyone who says that there are three places to be filled do not know what they are talking about. I am going to print off a few of these posts and show it to them when I pick the car up but I am confused and worried.

So back to the original question Can I carry the car to someone else and have them change just the Clutch Pack fluid or does it have to be done in the same precise manner as the Hydraulic side of the AYC system?

[Jimbo]

Clutch Pack fluid is on the diff, is a doddle to change, and doesn't need any special equipment. It is different to the AYC hydraulic fluid, although they are both ATF - this you fill from the cap on the RHS of your boot and ideally needs a special bleeding tool to ensure no airlocks.

I'd be rather concerned about your dealer, just as I was rather concerned about mine!

[Pizza]

Thanks jimbo for the response. I think I will have someone else do it if It doesn't require any special tools or procedures. Do you know where I could find a pick of the right bolt to pull for the Clutch Pack?

[richy rich]

pizza the rear dif has atf only stamped on it clearly both drain and fill.

there is a write up on here some where.

[Pizza]

Tell me are the Evo and VR-4 AYC systems the same because I was just speaking to the manager/owner and was trying to get the info across. I was told he does not care what anyone says because he has been in the business for over 20 years and they have worked on X number of Evos and he has pulled down ayc systems and built them and also worked on my car when the previous owner had it and there is no separate filling of the clutch pack.

I can draw several conclusions from this.

(1) I need to find another mechanic

(2) This car has never had it's Clutch pack fluid replaced (since the previous owner had the car serviced there)

(3) It sucks to be living in the 3rd World

(4) Begs the question how many peoples Diffs have been pulled apart at this shop when it could just have been as simple as a fluid change in the right place.

Anyway I just wanted to know what to point to when I pick up the car tomorrow. I realize that he has already made up his mind and really has no intention of listening objectively to what anyone has to say.

[richy rich]

i bet you still have them same problem when you get it back

[Pizza]

I'm sure of it. Right now I would just like to get it out of there but he's doing some other straight forward things on it for me.

Just to make sure... the above info applies to both the Manual (which mine is) and the auto right?

[Kieran]

I'm sure of it. Right now I would just like to get it out of there but he's doing some other straight forward things on it for me.

Just to make sure... the above info applies to both the Manual (which mine is) and the auto right?


Your car is a Type-S and not a Type-V, isn't it? Looking at your profile, you have a 1998 car.... Is it a facelift? Does it have the light-up dash with the AYC bars on it?

[Nick Mann]

I have worked on pre and post face lift VR4's. There are three fluids in an ayc system. There is a gear oil in the rear diff. A clutch pack fluid in the rear diff. And a hydraulic fluid controlling the clutch pack. If your dealer says that these three systems do not exist, he is either stupid or untrustworthy.

There is a good write up in the articles section, but you need to join the club to get into the members section.

[amsoil]

I was told he does not care what anyone says because he has been in the business for over 20 years and they have worked on X number of Evos and he has pulled down ayc systems and built them and also worked on my car when the previous owner had it and there is no separate filling of the clutch pack.

.

This reminds me of what was written but one Carrol Smith who wrote some of the very best books on suspension set ups and handling.
It was given as an example of what often happens when you try and query something you think might not be right. The final outcome is always the same .... you walk. Best to use other peoples experiences and do it straight away as its less painful and expensive!

[Kieran]

Your car is a Type-S and not a Type-V, isn't it? Looking at your profile, you have a 1998 car.... Is it a facelift? Does it have the light-up dash with the AYC bars on it?

Sorry - ignore that. I've just looked at your PhotoBucket page and you can CLEARLY see the AYC bars on your dash! I agree with what's already been said in this case.... Look elsewhere - you just know the job won't be done right otherwise!

[richy rich]

take this pic to your dealer and show him and tell him to shove his 20years up his @rse.

back to you problem 1 Q when going round slow left hand bends, is this with ayc active, IE do any of the green lights come on if so ayc problem if not i don't think it is a ayc problem id suggest it is more likely to be a wheel bearing.

[EdmundVR4]

Great info here. Thanks guys.

[Pizza]

Thanks for all the help folks. I intend to print off most of these comments and print the pic and show it to him. If he doesn't want to 'learn something new' then that's up to him and the future clients who will pay the price.

Sorry I was not on yesturday so missed some of the questions. To answer your question Richy Rich, Yes the AYC lights are on. As I said it normally happens after a spirated run ( I assume the heat of the fluids therefore has an impact) and when it is a very slow corner usually only 1 AYC light light ups and interestingly it's usually on a corner that when all is well they never come up on.

Thanks for the pic. Love it but could someone show me/tell me in relation to the pic where is the AYC Clucth 'FILL' point.
I assume the point that says 'Diff Fill' is Gear Oil.

[Nick Mann]

Thanks for the pic. Love it but could someone show me/tell me in relation to the pic where is the AYC Clucth 'FILL' point.
I assume the point that says 'Diff Fill' is Gear Oil.

Off the top of the photo and yes!

Like I mentioned before, there is a good article in the members section detailing the procedure and showing more photos.

[andja]

I have had my diff apart twice now, the friction material on the clutches is black so as it breaks down it makes the clutch pack fluid go very black, this doesnt take long long if you drive it like you should, 5000 k's easy. The diff oils ,all three kinds, do get very hot and will make more noise when they are hot, my car had done 60,000 k's when i pulled the diff apart the first time and it was full of black crap, so you may have to change the fluid 2 or 3 times to sort it fully. I reccomend new oil seals as well these stop the different oils ( gear oil and ayc fluid) from cross contaminating. Good luck. P.S. mitsubishi dont know anything about these diffs, they treat them as a sealed unit!!!!

[Subaru ETA]

there must be more than one mechanic where you come form coz this dude is a complete tosser! tell him to open his eyes next time hes under your car. feel sorry for the x amount of evo owners!

[newvr4]

Hi there all.. can i start off by saying what a great site..

I have just purchased a 97 Legnum vr4 done 45000(genuine) km/s and am having problems with potentially the rear diff/rear running gear as well. At 60km/h 2000rpm the car shudders (no noise just vibration) and it seems to be coming from the rear right corner. i.ve changed the diff oil (it was very dirty) and the problem is still happening.

Any help would be greatly appreciated.

[Nick Mann]

Are you sure it is not the gearbox? Search the site on gearbox shudder, especially if it only happens at low revs in 4th/5th gear.

[amsoil]

Best you join the club and help yourself to the vast knowledge these chaps have. You will get the joining fee back as soon as you get some oil (arrangements for a 10% discount have been made in NZ) never mind the savings and the ability to get that car running oh so swweeeetly.

:D

[Axeboy]

Could it be the wheel?

[bradc]

There could be lots of alignment and suspension issues causing it, as well as drivetrain. Probably easiest to take it to a mitsi dealership and get them to sort it.

[newvr4]

I'll start with the wheel and through process of elimination i'm sure i'll find something.. will keep ya updated

[newvr4]

Have done more testing on my car and its looking to be the 2 lage rubber bushes the hold the driveshaft in place (too much movment for my likeing. will replace and resume testing...

[richy rich]

there is no bushes holding drive shafts in place, i think you are talking about cv boots. there should be a lot of lateral movement so when suspention is going up and down the drive shaft can move as well.

[richieelliott]

my rear diff decided to go bang just before christmas when i took it in they said that all the bolts had worked their merry way out then the oil poured out then it overheated and gave up trying to work sounded like someone with a hammer underneath the car, got it aa'ed back to Plymouth now have to wait for the damage report both to transmission and to wallet

non stop for me

this is the third diff i have gone through in 2 years so im wondering perhaps theres something else wrong with it?

[Kieran]

this is the third diff i have gone through in 2 years so im wondering perhaps theres something else wrong with it?

Yep - the nut behind the steering wheel!/pan

[richieelliott]

SOOOO rude! hahahahahah maybe, do you think I should sell him?

[amsoil]

To loose 3 differentials like this really sounds like there is something fundamentally wrong. Do the diffs come from or are built by the same place? Do they all have really crap oil in them or has someone misunderstood and put ATF in them? IMHO there are so very few people out there who really know how to not only build but correctly set up a diff that it would be safer (and so much cheaper) to buy a second hand unit and have a quality oil (Amsoil suprisingly/ unsuprisingly comes to mind here!!) put in. You should really then be able to forget it almost forever.

[richieelliott]

they were second hand diffs but the first time the cogs destroyed themselves after a oil and fluid/change at a mitsy garage the second time was when my transfer box went shortly after my prop shaft and this time it shook it self to death!
Just call me lucky