Transmission Leak!

[Aronis]

I was smelling what I suspected Transmission fluid for the past couple of weeks. I did not see any drips on the floor until yesterday! I found a 8 inch puddle on the floor.

I put the car up on the ramps this morning and took a look. There is a leak on the passenger side just inside of the drive shaft input. I assume there is a seal there which needs to be replaced, but the bolts are not accessible without taking down the support which holds the engine in!

So just asking opinions here. If they dropped the engine to install the new TC a year ago, would they have necessarily disconnected the passenger side drive shaft in order to get the transmission out? If so, what would be your guess that they neither replaced the gasket, nor tightened the bolts properly (given that I found the oil drain plug loose!)

Was taking the car in for a new drivers side intercooler and 'while the front of the car is off - timing belt service, etc (although I had it done at 102,000 miles, now at 118,000 so early), and to have the rear differential serviced (strange sensation on hard acceleration - some said diff mount may be bad, who knows), but the earliest appointment is September 12!

How much leakage can I let go on and still drive daily to work?

Mike

(dumb bastards could not put a transmission dip stick in the car! D'ooh):lovl:

[hahnmgh63]

They do disconnect the axles but they do not do anything with the flange. There are bolts going from the CV joint on the axle into the flange. Someone posted here a while back about a leak there and had to have it redone something like 3 times as I guess it is a little tricky to drive the seal in properly. Do a search of the archives for it. I don't think removing the engine/transmission had anything to do with it though.

[Aronis]

Thanks. Extra letters.

[TozoM8]

You can remove the axle, then replace the seal. It holds gear lube not trans fluid. You can drive it for a couple days without trouble.

[Aronis]

Mechanic looked at my car today. He confirmed that it looks like a leak at the Axil seal.

He checked the fluid level which was still ok.

If the lube at that spot is Gear lube how is that lube replaced?

If it is transmission fluid then is that seal the real problem??

Thanks

Mike

[hahnmgh63]

The front differential doesn't have a drain plug, just a fill plug so you have to get a suction gun or pump to get it out.

[Aronis]

This is getting interesting. Now I want to find a good schematic for the transmission. So the output point for the drive axel (front) which appears to come out of the side of the transmission is actually a different chamber than the transmission? That is interesting.

So how much gear Lube is in that differential?

Is it slighty RED in color?

More importantly why didn't my mechanic make this distinction?

Tell me, if the front differential goes belly up due to lack of fluid how much of a job is it to replace that component? How does the drivers side and passenger side hook up as a differential? Across the body of the transmission, yet a separate fluid space?

Thanks,

Mike

[hahnmgh63]

Page 31 of the RS6 study guide has a picture that may slightly explain it, and section 39-2 of the Bentley manual shows the capacities of Front Diff 1.4qts, center diff .93qts, rear diff 1.6qts. The front & center differentials are incorporated with the Automatic transmission. The Center diff is bolted on to the rear of the tranny but looks to be part of the whole assembly. The front diff fill plug is at about the 2 O'clock position on the right axle flange, the Center diff fill is also on the right side about 10" forward of the rear output flange and about 2/3 of the way up the housing with the drain plug at the bottom of the rear tailshaft housing just below the fill plug. Maybe slightly Red in color going in but probably not after a few miles. It should have that rotten eggs smell that due to the Sulphur extreme wear additive that gear oils have. And yes, the front diff hangs out at the front lower part of the transmission across the body of the tranny with different fluid than the tranny. 75w/90 GL5 gear oil in all diff's and ATF meeting Exxon (now Mobil) grade ESSO LT 71141 (preferably a synthetic replacement).

[Aronis]

THANK YOU!

I'm guessing access to that fill hole is PAINFUL! otherwise I'd top it off and keep driving normally!

I'm just carefully driving (to and from work). I'm off next week, so the car can sit until my 9/12 appointment.

Thank you for the feed back

Mike

[hahnmgh63]

The fill hole for the front differential can be easily accessed by removing the right front wheel if you don't have a lift and jackstands wouldn't be good since the car wouldn't be sitting level. I can't remember which but it is either a Torx or Allen/hex head to remove.

[Aronis]

Great.

I use modified ramps (since lowering my car I cannot drive up on the ramps, had to add a preramp made of 2x10s (two layers) so I pick up 3 inches of height.) Then while up on the ramps I jack one side, place floor jack stands, and remove the wheel, etc.

Not front to back level, but side to side, should be ok in a pinch.

Mike

[TozoM8]

It has to be level or you will overfill it and it will leak more for awhile.

[hahnmgh63]

I would just jack it up, remove the front right tire and lower it enough to make the car level again, which should be well before rotor contact with the ground. It doesn't need to be jacked up high in the air to get at the fill plug, just need the front tire removed if you don't have a lift.

[Aronis]

Cool!

I'm benching it until 9/12. Drove too agressively this am (vette on my tail on on ramp, god that's fun.)

I'm on vacation next week anyway so I'll be driving my John Deere for the week (putting in lawn)

Minivan "drop off" at work the rest of this week, cant leave my wife without her car.

Mike

Thanks for all the help. If only you lived on my street!!

[Aronis]

Which side is the fill plug on? Drivers or passenger side?

If one on each side, are they separate oil volumes? Or 1.4 liter total for both sides together?

Thanks

[hahnmgh63]

Passenger side.

[Aronis]

11692


Which plug? Top or Bottom? I am assuming the top is for filling (smaller one) and the bottom is for draining (the larger one).

Thank you,

Mike

[Aronis]

my bad, that top bolt, greenish color looks like a mounting bolt and not a plug LOL..

[hahnmgh63]

11694Remember, the front diff only has a fill plug, no drain plug. Look at the CV joint from the side and the fill plug is at about the 3 O-clock position.

Center Diff on the back of the transmission fill & drain plugs.
11695

[4everRS]

It is on the other side of the axle from your pic.

[Aronis]

I saw this first but it's not a torques and not a allen??

I cleaned it out as you can see expecting to see what type of wrench to use.

HELP!


11693

[hahnmgh63]

Aronis, that is the correct fill plug. It looks a little strange because of the machining but it does take a 8mm allen and I double checked it on both transmissions that I have and my rebuilder actually had the plug loose with a tag attached saying fill here with the here with the proper synthetic gear oil....and about 5 years ago I evacuated about a quart of gear oil and refilled and all was well ever since. 4everRS, if your talking about the plug looking bolt on the other side (left) that has a lot of factory loctite on it? I'm not sure what this is but I wouldn't touch it, maybe Tozo can chip in to say what it is but it is labled a bolt in ETKA and the fill plug on the right is labled plug w/seal.
11696

[TozoM8]

Aronis, that is the correct fill plug. It looks a little strange because of the machining but it does take a 8mm allen and I double checked it on both transmissions that I have and my rebuilder actually had the plug loose with a tag attached saying fill here with the here with the proper synthetic gear oil....and about 5 years ago I evacuated about a quart of gear oil and refilled and all was well ever since. 4everRS, if your talking about the plug looking bolt on the other side (left) that has a lot of factory loctite on it? I'm not sure what this is but I wouldn't touch it, maybe Tozo can chip in to say what it is but it is labled a bolt in ETKA and the fill plug on the right is labled plug w/seal.
11696

That is a diagnostic port to check main pressure. The fill plug for the front diff is 8mm allen.

[4everRS]

Mark, I was responding to the pic Mike posted. We responded at the same time (you had fancy pics though). So ya, I am talking about the same fill plug you are. And I have no idea what that other bolt is either

[TozoM8]

I saw this first but it's not a torques and not a allen??

I cleaned it out as you can see expecting to see what type of wrench to use.

HELP!


11693

8mm allen. Yours is leaking a lot. You need to grab the axle close to the diff and move it up-down. I bet it moves a lot. A new seal will not last long. You will need to shim the outer bearing race to minimize the output flange play or it will eat up the new seal fast.

[hahnmgh63]

Ok, his (Aronis) second pic above here on pg 2 is the correct fill plug, on the right side, and unless it was changed, guaranteed to take a 8mm allen, and the one in the pic looks just like the pic I posted and on both of my transmissions.

[Aronis]

Tozo,

Could you expand on the Shimming?

Do you mean shim between the flange and the end of the axle?

Do you have any photos of such?

Anyone else have a photo of the seal itself?

Considering DIY this weekend. I am at least going to top off the gear oil so I can drive if needed. (so I can get the car to the shop at the very least without doing damage).

Thanks everyone.

Mike

[hahnmgh63]

The bearing is moving too much, too loose. Probably need to start with a dial gauge and measure the runout of the shaft. ZF probably has a manual that lists the specs and where the measurement is taken from. Then you would install thin shims behind the bearing race or against the face of the bearing so the contact between the bearing & the race isn't so sloppy. This is a generic discription as I haven't had mine apart before to see what it looks like. If there is too much play between the bearing & the race the whole shaft cab wobble slightly which causes the seal to wear faster as it is flexing much more than it is designed too. A transmission rebuilder like Tozo probably has all of the specs, I have a copy of the ZF parts book somewhere but it doesn't list assembly specs/tolerance.

[hahnmgh63]

Ok, still no specs but I found the listing of the different sizes (shim thickness) of shims in the ZF transmission parts book. A picture of the front diff is on pg 19 and the shims begin on pg 41 or pg 42. This is not the BCY tranny but probably a A6 4.2 or similar enough that the shims are probably the same, but I still don't have the runout tolerance or where to measure from. If you want the ZF Manual send me your E-mail address, it is only 1MB but I can't upload it here.

[Aronis]

Yes. A copy would be great. Pm sent

[Aronis]

Ok. I pulled the fill plug and confirmed the leak by the odor!!

I added about 1/3 quart gear oil.

Yes, Tozo, there is play at the flange. Darn!!

So is that a typical wear and tear thing for 120,000 miles?

If there is no puddle there in the morning I'll be able to drive to work.

Thanks for all the help

Mike

[hahnmgh63]

By play, are you tring to rotate the shaft or move it up down? There will be some rotational play in the differential but it is the up down/side to side play we are talking about.

[Aronis]

Little rotation I expected, there may be a little side to side.

I'm going to have to depend on the mechanic to do the correct thing.

From the transmission PDF you sent, it appears one removes a bolt from one flange and the othe comes out with the shaft from the heart of the differential.

If so the I guess you have to remove the axle to slide they shaft out? Or is there a bolt on each end if that shaft?

Mike

[TozoM8]

You have to do it on the lift. It will take a couple hours.
Remove wheel. Remove the lower front control arm from the sub frame. Remove the lower rear control arm from the spindle. Remove 6 axle bolts (triple square). Remove the big outer axle bolt. Remove axle. Support engine and transmission from the bottom. Remove engine and trans mount bolts from sub frame. Lower sub frame to gain access to the diff bolts all around. Remove output flange bolt (T40 ). Remove output flange. Remove trans mount. Remove all bolts from the diff housing (some is behind the turbo air output pipe). Remove diff cover. The driver's side output flange should hold the diff in the trans, but just to be safe pull it off and set it a side. Remove bearing outer race and the shim behind it. you will need more or thicker shim to fix the play.

[Aronis]

Tozo,

It sounds like the audi mechanic will have some fun that day!

I doubt those shims are a stock item at the typical Audi Dealership!

How should I approach him with regard to the need for the shims if he does not believe it is necessary?

My original seals lasted for 120,000 miles, he may be 'certain' it's just the seal and not that play.. any recommedations on how to convince him of the need for the shims?

He did recommend changing the seals on both sides. (I'm still a bit concerned that he did not correct me and tell me it was not transmission fluid but differential gear oil that was leaking, maybe I'm reading into that too much?)

Thank you,

Mike

[TozoM8]

I would not take it to Audi. They are not allowed to open the trans so not much experience there and they will not have the shim for sure. Find a good trans shop in your area. They did this a bunch of times already and will have the shim in stock.

[Aronis]

I would but Chicago is just too far to drive with a leak of this nature! LOL...You want to come to Binghamton for a visit? I can get access to a lift:)..

Mike

[Aronis]

When the Seal is replaced, isn't the spot where the shim would go also exposed?? I am assuming the shim you are speaking about is a metal collar which fits into the now Loose opening where the seal goes???

Mike

[TozoM8]

No, it goes inside the diff housing.

[Aronis]

Oh, bummer!

Perhaps a visit to Level Ten? Have the "upgraded" Level Ten work done, and be done with it for another 100,000 SMiles...

Thanks again.

Have a great day.

Mike

[TozoM8]

I sent you an email with pictures.

[Aronis]

Thank you.

I spoke with the mechanic today. I asked him about shims generically and he immediately made it clear to me that he both knew exactly what Tozo was referring to and if needed will install new shims. In his experience those seals often go as a result of outside dirt/debre wear and tear. So I'll know more Monday.

Also I Parked my car outside, in the rain, tipped down hill for five hours and the front passenger side flooded. Cause TCU to go to limp mode. I had to drive today for a meeting, short drive. I was literally right down the street from my Audi dealer!! Dropped it off there right away. When the service guy drive it into the garage it was ok just a remaining CEL was on. So I hope the TCU did not fry!

This is a COMMON leak in the 2003 A6. Not sure I have seen much here. I had my windshield replaced about a year ago and the bottom plastic strip never appeared seated just right. I suspect that with the tipped downhill angle and four hour of rain I ended up with enough water to screw things up there was a Puddle in the passenger foot well. They said my auto insurance may cover it!!

Mike

[hahnmgh63]

It may be true about dirt & debri getting on the seal but if you can feel a fairly noticeable amount of side to side or up and down play then the bearing needs to be replace and/or shimmed or else the next seal will wear out very prematurely. If the mechanic says the play is fine then make him give you a guarantee that it won't leak for a year or two at least since two years is probably a long shot for the seal to last again if there is a fair amount of play. There was a recall whcih included the RS6 that I received about a year or year and a half ago regarding the front sill drains, I park my car inside and do most of my work so I didn't take my car in. Also, stay away from Level 10, they did some good work 5 or 10 years ago but when Sam left to star 517 trans all of their work now has been noted as garbage by the S5 A6 4.2 crowd.

[Aronis]

Seals replaced. No play found at drive shafts. The bearing housing shims where check and measured. No play!

The seal which leaked showed damage from the outside.

Center diff and rear diff service in the morning.

Rear diff according to the mechanic does have clutch packs. We will see when he gets into the rear diff.

Rear diff mounts appear fine.

Intercooler being replaced (stock).

Rain entry damage fixed and covered by my auto insurance.

New TCU from Germany installed.

Hopefully I'll have the RS6 back early next week.

Mike

[kismetcapitan]

thank god my car's previous owner had Level 10 work on my transmission!! One less thing to worry about...

The rain leaking in...that just sounds nightmarish and fate being unnecessarily cruel!