Hi there

Just the other night I could smell a strong burning oil smell coming from somewhere on my car. When I came to a stop smoke was pouring from the underside and it stunk real bad, I had a closer look and could see oil dripping quite fast from my rear diff onto the exhaust causing the smoke.

I took the diff out and from what it appears that the ATF fluid from the AYC clutch plate side has come out the overflow port on top of the diff, What would cause this? my guess is that someone never bled it properly in the past, the ATF is black and STINKS real bad, the ATF in the boot and lines when I disconnected them from the diff is nice a clean and still red.

All the gears are in mint cond, nothing broken what so ever

Ive pulled it all apart for a good degrease and about to reassemble it, does anyone have a good diagram or video of how everything goes back together? Its on a Evo 5 (but I think there all the same) and any ideas what would cause this overflow leak and the fluid burning up?

Cheers

 

one of your AYC actuators in the diff could have broken.. that would cause the fluid from the pump (boot) to leak into the diff and overfill the diff with oil causing it to leak out..

also check the housing... it might have broken... You should check the fluid level in the boot reservoir... if you are loosing fluid there, then the cause is probably a broken actuator in the diff.. There are two, basically plates in the diff housing, pressing onto the clutch pack..

I took apart and rebuilt a couple of them, but those were Evo 9 units... however similar they are.. I can help you if you get stuck.. it is not difficult..

 

What does a broken actuator look like? everything appears in good cond inside, no cracks or broken bits anywhere.

Not loosing fluid in the boot at all.

That doesn't really explain why the fluid in the diff was black and the fluid in the boot/lines are still clean and red.

Would you be able to send me a daigram or pics of what goes where? there are lots of little bearing etc and dont want to mess it up.

 

fluid in the boot is separate from the fluid in the diff.. If you are not loosing the fluid from the boot reservoir then the actuators in the diff are ok.. But, I have no explanation then why you would have oil overflow from the diff...

You should have two different oils in the diff.. one is normal gearbox oil, in the front part of the diff, covering ring and pinion and the open diff.... second is the red ATF fluid, which covers the two sets of clutch plates and the speed up and speed down gearbox.. This fluid will go black if not changed regularly...
Are you sure the oil is coming from the overflow vent?

here is the sevice manual.
http://www.scribd.com/doc/38750992/G...#outer_page_14

can you make some pics of you diff... I have one E9 unit in my basement, I can open that one again and give you some pointers..

 

Cool thanks heaps for the help

Im pretty sure it was coming from the overflow, it was hard to tell as it was caked in oil when I removed it. There are no cracks or leaks anywhere else for it to come out, and the smell it was giving off was pretty bad.

The diff section oil was nice and clean but the AYC side STUNK!! unless this is normal for ATF fluid.

I can't see anything physically wrong with it. Will get some pics up later

 

I understand that the fluid in the boot area and lines are separate from the diff itself. There is no leak between these two parts as far as I can tell, if there was my guess would be the fluid in the lines/boot would be burnt/black as well since they would be mixing, but they are still clean and red.

Would something inside the AYC section be locking up, causing the ATF to heat up, cook and boil out the overflow?

Or would a pump failure cause lack of movement in the diff causing the fluid to burn up?

I can't see anything physically wrong with the internal parts, everything appears in good nick

The smell is pretty unreal, stinks out the whole house

 

Ok so heres what Ive found.

Ive degreased the parts and found the larger section of the AYC case has 'Evo parts 06/07' etched into it meaning its been changed in the past at some point

Now the only thing I can spot is on the larger section of the case had some of that instant DIY weld stuff typically found at repco covering a section (the silver looking bit just to the left of the bleed valve, where a ball type seal sits) so I chipped all that crap off as best I could and found the ball seal still in there, but just blew through the feed line and had the other end covered with the bleed nipple and I could feel a very faint leak in that area so will get that welded up properly.



These are the two 'ends' of the clutch pack section (one sits on top of the other), which when activated through pressure in the lines, push the inside of the ends against the clutch packs (someone correct me if im wrong)



My guess is that tiny tiny leak over time has caused small amounts of air to enter the AYC lines causing an air bubble (in effect the same way brakes are not bled properly) and therefore causing an issue.

None of that explains why the AYC section was leaking from what I assume was the overflow (difficult to tell since the whole underside was caked in burnt ATF which STINKS!!! but def coming from the diff itself. Since the pump/line/housing fluid is separate from the boot/lines fluid. Lines/boot fluid was still clean and red and fluid levels in the boot never went down so I assume it wasn't leaking into the housing since that fluid was still clean and would have some blackness in it from mixing/leaking.

When I drained the AYC it STUNK but the diff gear side was fine and still clean leading me to believe its def the AYC.

Maybe the slow leak from the dodge weld caused it to eventually lock something up and boil over?

I have no idea really, desperately need it fixed in 2 weeks!

 

Just had a thought.

I put in a aftermarket steering wheel just to get an idea of size/feel etc, could this have any effect on it? only things connected to this is the airbag and horn though, both of which were disconnected with the aftermarket wheel when the diff started spitting oil

Is the steering wheel/horn/airbag linked to the AYC in any way? would this have any effect?

Sorry if it sounds noob but Ive got no idea what the problem could be

Might have found my problem

http://www.lancerregister.com/showthread.php?t=345676

 

Is the steering wheel sensor (the round metal disc behind the clock spring) linked to AYC in some way?

I put an aftermarket wheel and boss kit in and didn't line up the white tabs that slot into the boss so that when the wheel is turned it turns the sensor.

Instead it stayed in one spot, not lined up properly, so my guess is that the sensor was in such a position that it was telling the AYC to be on all the time, causing the oil to cook and boil out the overflow

I didn't really think about it as I was just testing out the size/fitment of an aftermarket wheel.

Could also be faulty g sensors but they look in good nick

Gave me chance to fix my rooted diff bushes anyway.

 

yes, the steering wheel sensor is integral part of the ayc... If you have evoscan and cable, you can check if the sensor is aligned propperly..

 

Ive just put the stock steering wheel back in for the time being, Only lines up with the clock spring and tabs one way.

I feel like a right n00b, but my diff bushes were stuffed and the diff would smack the underside under hard quick shifting so at least ive sorted that out, nice new filled solid bushes no.

 

you really should try to log the steering wheel sensor position, and see if it is positioned and calibrated correctly..