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Quattro Drive Line Fluids

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Old 07-24-2014, 07:57 PM   #1
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Default Quattro Drive Line Fluids

SO, what are the recommended fluid for the rear diff and the center diff (Transfer case).

I have some seeping seals, and don't want to dig into them right now, but want to check (and top up) the fluids.
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Old 07-25-2014, 08:06 AM   #2
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Seems factory is Fuchs Synthetic, and lots of people like Motul 300 or Liqui Moly.
And lots of people ask about Mobil 1.

Of course all the discussions then break down into arguing over GL4 vs. GL5 in transmissions and the effect on brass syncros, and the question as to which fluids are ok/best for the Diff and center Diff are lost.
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Old 07-25-2014, 08:36 AM   #3
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Test Post...
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Old 07-25-2014, 09:26 AM   #4
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Test received, 5 by 5!
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Old 07-25-2014, 09:34 AM   #5
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Test received, 5 by 5!
Please use quote and reply so posts are threaded correctly.
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Old 07-25-2014, 10:01 AM   #6
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center diff is not a transfer case. It is a torsen diff.

In general, there is little advantage to using other than audi fluid - its not that costly. I'd avoid mixing fluids unless you know that they are compatible.

OEM fluid is ESSO LT 71141 9 according to the guys who make it, ZF)

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Old 07-25-2014, 10:45 AM   #7
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center diff is not a transfer case. It is a torsen diff.

In general, there is little advantage to using other than audi fluid - its not that costly. I'd avoid mixing fluids unless you know that they are compatible.

OEM fluid is ESSO LT 71141 9 according to the guys who make it, ZF)

Grant

That seems to be the ATF not the diff fluid, but not sure on this car if the center diff is lubed with the AT or separately.

"Transfer case" is used fairly generically to describe the piece of the driveline that send power to the front and back axles.

So is it ATF (or the proper kind), or Gear Oil (of the proper kind)?
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Old 07-25-2014, 12:05 PM   #8
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Quote:
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So is it ATF (or the proper kind), or Gear Oil (of the proper kind)?
Assuming your car is a slushbox:

Front diff takes gear oil. Automatic section takes ATF. Center diff takes gear oil. Rear diff takes gear oil.

Front, auto, center sections are combined into one unit with three distinct chambers. If you have ATF in your center diff, either someone installed the wrong fluid or you have an internal seal failure.
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Old 07-25-2014, 04:40 PM   #9
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Sorry, brain fart. Yes, the spec i gave is for the transmission, the final drive/diff uses gear oil. Check the specs in the manual. The center/front one is combined final drive and torsen i believe

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Old 07-26-2014, 11:36 AM   #10
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So back to the question I asked.

Any gear oil, or some specific brands/types?
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Old 07-30-2014, 05:22 AM   #11
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If no one yells soon, I am just going to top up with Mobil-1 Synthetic 75w-90.

It is just a top up since the shop said the seals were seeping a little bit. (no drips seen), but I want to hold off on doing that work for a while.

Anyone else have Transmission Propeller shaft seal and/or Rear differential axle seals leaking?
If so, how hard to replace and how bad was the leak?
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Old 08-13-2014, 10:28 AM   #12
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OK, one last (Probably not) question:

Is the center Torsen Diff drained and filled through the same plugs as the front diff?
The car is a 2.8 Quatro with an auto trans.

I have a PDF manual, but it is not clear, it just talked about the front and rear differential, and is silent on the center diff.

It gives a capacity, separate from the Front Diff and Transmission, but does not show the filler, drain or any particulars about the level.

Rear shows typical fill till it runs out, and front is measures some distance below the hole with a shop made dipstick (bent wire).
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Old 08-13-2014, 06:48 PM   #13
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Front and center diff are separated by the automatic section, so no, they have separate fill holes.

IIRC, the front diff does not have a drain plug. Fluid must be sucked out.
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Old 08-14-2014, 04:40 AM   #14
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Quote:
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Front and center diff are separated by the automatic section, so no, they have separate fill holes.

IIRC, the front diff does not have a drain plug. Fluid must be sucked out.
Have any good pics as to where the center Diff plugs are?
Does it fill to the hole, or some other measurement like the front?
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Old 08-14-2014, 11:18 AM   #15
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Front diff is a plug with an 8mm allen socket right below the passenger drive axle flange. The torsen fill plug is also an 8mm allen on the passenger side of the torsen. Audi just calls for Synthetic 80w90 gear oil. Its the same torsen thats been used since the 80's. Its nothing special. Just use the mobile, my A6's has been full of mobile 1 for 20k+ miles now.
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Old 08-14-2014, 11:30 AM   #16
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Did you do the whole dipstick thing for the front level, or just top up like a normal diff?

What about the center?
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Old 08-14-2014, 05:27 PM   #17
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while the car is level just pump in oil untill it runs out the fill hole.
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Old 08-14-2014, 06:17 PM   #18
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Hmm???
Attached Images
File Type: jpg Front Diff.JPG (36.5 KB, 43 views)
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Old 08-16-2014, 09:59 AM   #19
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Well . . . .

Rear diff was fairly easy. Filler bolt was very tight, but once opened I found the Diff low.
Given the wetness around the axle seals, it was expected.
Took about 3 or 4 Oz of oil, maybe a little more. (Guessing a bit)

Center diff was next. It beat me. Diff=1 : Me=0
Between the limited space under the car (Front on ramps and back on jack stands), the angle of the plug, the exhaust in the way, I could not get enough leverage to open it.
Will come back to it next time it is on a lift.
Since the rear seal is wet and was showing bit of a drip, I really want to double check the level and top it up.

Front diff was easy. Off the ramps and stands, just jacked up the Rt front, took off the wheel and the plug is an easy reach with some extensions and a flex-joint. Plug came out easy. Made the dipstick (Bent wire) and checked the level. All was good.
Since the plug opened fairly easy, I guess it had been topped up sometime.

Did find that whatever "Mechanic" (and I use the term with a good amount of sarcasm) last worked on that corner should be flipping burgers (assuming he can do that without F-ing up).
FIrst the lug bolts were REALLY tight. OK, some tighten with time, but these one cracked come out so easy. A quick look showed that they had been coated with white grease (guessing lithium grease or maybe some spray Teflon grease), so they were obviously over tightened since the torque spec is for dry threads.
Next, I find the inner wheel well cover was rubbing the tire. Seems it was removed (or at least the front edge was unscrewed and none of the screws were reinstalled.
SO, I figure I will temporarily steal a few from the rear of the cover and at least hold the front in place and away from the wheel. Of course that did not work because the plastic clips the screws go into are all broken or missing. My guess is the "mechanic" either pull them out or over tightened them and broke the clips.
So temporarily the cover is held in place with plastic push in body pins.

One more thing to fix!
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Old 09-10-2014, 06:52 AM   #20
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One last attempt.

I think I was trying the wrong bolt or plug on the center diff, so before the car goes to Buffalo for the winter, I am going to try one more time to top up the center diff.

So here is the question:
Does anyone have a picture or drawing of the transmission/center diff showing the filler plug?
I have looked on line and all I find are pictures from the drivers side, or cutaways.

If you have a spare transmission sitting, I would love a quick pic.
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Old 09-10-2014, 06:52 AM
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