Help! Rear diff fluid change gone wrong. Side of road now!

[Jay@JXB]

Just changed the fluid in the Sports Diff. Drained through this hole.



Filled through this hole.



Got less than a quart to go in. The tube I used to fill was a tight fit in the fill hole and about a quart in oil started coming out the top and dripping down from somewhere.



I took the tube out and there was a lot of oil leaking. I let it drain it down til it stopped coming out the fill hole and plugged it up. About 10 miles down the road I'm getting a low whiney grindy noise coming from the rear...what did I do?

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[Jay@JXB]

Fresh fluid appears to be leaking out from the top still. I'm under it now. What could have blown seal as a result of me overfilling and/or pressurizing the Sports Diff?



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[LaCross]

Sounds like you drained the fluid and tried putting fluid in the wrong hole.... I hope you havent got the same problems with women...

[Johnnycash]

ouch!

sounds like its gonna be an expensive repair, if the diff is broken.

[jran76]

Your pictures are little hard to figure out. Is it possible you drained the diff, but tried to fill the ATF fluid? Both are in that area (stupid way to do it....).

Edit: I can't really tell what you are pointing out in the second/fill picture.....

[Midnight_Rider]

What fluid did you use? Weight?

Also, what sound was it making when you turn?

[The Fat Kid]

You took a punt on servicing the second most expensive component of the car? Yikes...

Call a tow truck and bring it to an indie or the dealer. Do not attempt another DIY on the side of the road.

[chaos2984]

Sounds like you need a rear diff. Sounds like the gears ate themselves up. Did you look to see how much fluid the diff takes? If you couldn't put that amount in give or take a little bit some bells should of went off in your head like something is not right here. Did you look up the manual on what exactly was the fill hole?

[jimrobbington]

Ouch! Good luck!

[agorich]

hopefully it isn't as bad as we are all thinking. good luck with it. let us know what goes down. get the flatbed out there though!

[fitzydude]

I'm trying to orient myself from your pictures..

Edit: I believe you drained from the passenger-side drain plug (diff oil) and filled the driver-side fill hole (smart-diff ATF fluid). So it appears you drained the Diff oil and topped off the ATF smart-diff fluid with the wrong oil type.


Are you still under warranty??? I think you could play this right to get it covered.. You could half-way fill the diff with fluid and have it flat bedded to Audi. When they say you need a new diff you could blame the leaky seal which caused the diff oil to leak out. This is a known problem for early S4's. Of course if you do that you're a turrible person.

[scottycs]

definitely appears you filled the wrong hole. Should have been pretty obvious as what you drained and filled are different (gear oil vs ATF). Expensive mistake.

[skiptowncat]

http://www.audizine.com/forum/showth...t-Differential

[chaos2984]

http://www.audizine.com/forum/showth...t-Differential

Looks like you roasted your diff. According to this write up and your pics you drained the gear oil and you tried to fill through the ATF hole. No Bueno. You might be able to save it but your probably done. You can fill the diff up and then your going to have to flush out the ATF circuit. to get whatever gear oil got in there out. Or you will ruin the clutch plates. My guess is that the diff is roasted.

[Works2shoot]

I wonder if the car that Danger is parting out has an extra sport diff for you?

[B8 S4]

Whops, saving $500 turned into spending $5,000

[infinkc]

http://www.audizine.com/forum/showth...t-Differential

op read this, dont drive that car anymore till you get the fluids changed out and filled.

[hotleadsingergu]

Gotta agree with everybody else...your diff was empty and grinding. Good chance the gears are completely ripped up already.

[BlownOne]

Even if there was minimal fluid left after draining, the gears and clutches still had some protection. As long as you pulled over AS SOON AS YOU HEARD THE GRINDING, you have a chance of saving it. You're going to have to flush both fluids thourghly, then refill and test. Or take it in as is and play stupid if you have warranty. Good luck

Will

[BoostEasy]

It sound like you definitely filled the wrong hole. I'm a little perplexed on it potentially being the trans fill but I've never got under there and checked myself.

Diffs are never fully filled with oil AFAIK, only about 1/3 to 1/2 is typically submerged while at rest. so if you got overfill leakage, that would be a do not drive right there. If you manage to add to the trans, it's a guess on what might happen, depending on how much.

My 2c is bring it to the dealership or a good indy that knows Audis or similar DSG/DCT/PDK cars and fess up and see what they recommend.

There's a decent chance both the trans and diff will be ok but it depends on how far you drove it under how much load etc. Diffs themselves are pretty tough but the helical gears are very sensitive to wear pattern before they start to make noise. It might be ok with a slight whine once you put the right gear oil back in.

Good luck.

[chaos2984]

It sound like you definitely filled the wrong hole. I'm a little perplexed on it potentially being the trans fill but I've never got under there and checked myself.

Diffs are never fully filled with oil AFAIK, only about 1/3 to 1/2 is typically submerged while at rest. so if you got overfill leakage, that would be a do not drive right there. If you manage to add to the trans, it's a guess on what might happen, depending on how much.

My 2c is bring it to the dealership or a good indy that knows Audis or similar DSG/DCT/PDK cars and fess up and see what they recommend.

There's a decent chance both the trans and diff will be ok but it depends on how far you drove it under how much load etc. Diffs themselves are pretty tough but the helical gears are very sensitive to wear pattern before they start to make noise. It might be ok with a slight whine once you put the right gear oil back in.

Good luck.

The rear diff uses ATF fluid to control the clutches in it. Also you fry the pinion and carrier bearings first before you damage the rin and pinion. The Pinion is the first to go. My guess is he damaged its lifespan and might be able to put fluid in it and get it to go again but longevity it out of the question. But I would fill it up clean it off maybe blow some dust on it and if you have warranty and take and in and be like there is a noise in the diff I don't know what happened.

[skiptowncat]

The rear diff uses ATF fluid to control the clutches in it. Also you fry the pinion and carrier bearings first before you damage the rin and pinion. The Pinion is the first to go. My guess is he damaged its lifespan and might be able to put fluid in it and get it to go again but longevity it out of the question. But I would fill it up clean it off maybe blow some dust on it and if you have warranty and take and in and be like there is a noise in the diff I don't know what happened.

If you're going that route, put the old gear oil back in. Fresh oil is a dead giveaway.

[LaCross]

kinda makes me glad I have the non-sports diff

[Oloung1]

kinda makes me glad I have the non-sports diff

we can't post stuff like that here, we will get banned

good luck OP on your repairs!

[B8 S4]

kinda makes me glad I have the non-sports diff

Why's that? You still have to change the fluid....

[LaCross]

Yea but it's cake to change and cheap to replace

[Pared]

You put it in the wrong hole. Only problem is this time YOU'RE the one upset.

[DannyDeez]

You put it in the wrong hole. Only problem is this time YOU'RE the one upset.

Lmfaoo. Cried when I read this

[Vanimal]

What mileage is a good heads up to change the rear diff fluid? Even if you don't have the rear sport diff? I looked at the Audi interval service chart and it only shows info for the RS5. So i assume they are giving this one a lifetime guarantee as well" Rolls eyes"

If they are "saying" lifetime i assume 85-100k would be a nice number if you planned to keep the car past 100k.

[S4Drew]

I am cringing for you OP.. I hope it's not as bad as everyone thinks.