So I did some web research first, but I just need to throw out the questions again and confirm.
Rear diff = GL5 or GL4
Front diff = GL5 or GL4
ATF fluid = Audi or equivalent ATF fluid
Front Diff does NOT share fluid with ATF
Quattro diff = ?
When I had my ar iirc changing the quattro diff but I dont remember if it was when i had the auto or 6mt in there.
The front differential and transfer case have a shared supply of gear oil.
Here is a link to the ZF spare parts catalog which gives filling quantities and oil types.
http://www.vaglinks.com/Docs/Catalogues/ZF.com_6HP26A_61_Catalog.pdf
I went with the ZF Lifeguard 6 when I did my resealing job about a year and a half ago
Right they are “shared” from the tubes and cooler shown in your thread above but still need to be filled seperatly with the same fluid, got it. According to the manual it is called SAF AG4 1.04L for the transfer case “center diff” and 1.2L for the front diff. The ZF Lifeguard 6 for the ATF fluid.
What fluid did you use for the differentials in lieu of the SAF AG4?
This looks like a job I’ll do with the engine out so that I can re do the seals like you did when I do my cats this winter.
Pls document here w pics. Would be very helpful (and MUCH appreciated). TIA.
Regarding my choice of gear oil, here is an excerpt from the text that I started composing for my transmission thread.
For gear oil in the front differential and transfer case, ZF specifies SAF-AG4 with 4% Sturaco FM 1992. The SAF-AG4 is just a Castrol branded synthetic 75W90 gear oil. The Sturaco FM is a friction modifier that is added to keep the friction elements in the centre differential “happy”.
The gear oil listed under ETKA is G 055 145 A2. If you look around online, you will find that it sells for about $80+ /L which is insane if you ask me. From my research, this oil already contains the FM component which must be why it is so expensive. I decided to go with G 052 145 S2 (synthetic 75W90 gear oil) and add the FM separately.
I found a fellow on eBay in the UK and he was selling small quantities of the Sturaco additive. He had to purchase far more than what he required for his Audi because the transmission shop where he purchased it from would only sell it in full containers.
Interesting and thank you for the clarification. I wonder if my dealer would sell me a little…
The manual states that the addative of 4% Sturaco FM 1992 is only required when “replacing” the differentials, not a fluid flush. Am I reading this incorrectly?
Bring up an old thread, but it’s so good it’s not a bad thing…
Please confirm a few things:
–I can’t replace the transfer case/front diff fluid, unless I remove the front axle side covers (if so, I’ll have to wait to do at engine drop)
–this kit only comes with 8L of trans fluid:
–the rear diff takes 0.9L (p/n G052145S2: ~$28/L)-what other fluid is recommended?
Thanks, guys.
I was able to do the front differential fluid when I rebuilt my front suspension. The CV axle shield is only three bolts and easy to remove. I had to use a 8mm hex bit and a 8mm wrench to get to the plug.
Servicing my transmission was only 4L from the pan. I wasn’t able to do the filter because it requires dropping the exhaust.
For the rear differential, you can use any GL5 gear oil. Same for the transmission. Any spec ATF will work.
I just did Front and Rear Diff and Trans Service on my S6 the front and rear diffs took 1 quart each while the tranny took about 10 quarts of Oil
I understand exhaust with flex pipes have to come off to drop pan. Any tricks? How difficult was this?
Also, how did you drain front diff/transfer case?
I’ve been using Redline 75w/90 in the rear and Front/Center diff in the wife’s A8 (6HP26) for almost 10yrs. I put it in the car when the warranty ran out and it now has almost 80k on the fluid. Instead of the Audi or ZF Lifeguard I used Redline D6 ATF which is a full synthetic replacement. Car seems to shift better when real cold than the OEM fluid use to. Getting ready to change them all again, car runs so good I can’t see getting rid of it.
Thanks for the info.
Anyone else using Redline or have any opinions on using non-OE fluids?
I have been using Redline products (oil, PS fluid, trans & diff) for years in all my cars. Based on the results I have seen it is one of the best products out there.
Ed
I have been using Liqui Moly for most of my fluids. Their ATF works pretty good for a fraction of the cost.
Post up a few pics here of the locations to tap to fill.
This is what appears to be the diff cooler return line where I had a visible leak and replaced the oring. I also replaced the orings that seal the oil coolers to the bottom of the trans. When removing the diff cooler there was a fair amount of fluid that leaked from the diff. Assuming I can just fill the front diff and it will fill the oil cooler?
The .pdf mentions .2L in the cooler and pipes so wondering if I should fill from the top where I replaced the oring to fill the pipe and cooler…
The manual states to drive the vehicle after filling so the pipes and cooler can fill and then check the diff level again…
Also I bought some royal purple 75-40 diff fluid GL4 GL5 today because I was being lazy and just went to autozone. Any reason why I should not run this royal purple fluid in the diff and instead use oem or redline?
Here is a doc I put together when I did my ATF fluid work. It might help someone.
Ed
C6 S6 ATF Fluid Change_1.pdf (1.8 MB)
Thank you, I did reference that document.
I ended up pumping fluid into the lower “front diff” by pumping fluid thru the above mentioned hard line until the fluid draining from the front diff was new. I ended up not adding new fluid/removing fluid from the center diff because the trans mount was in the way. I’ll check levels after a 5 minute drive. Extracting the oil was not possible for me
For the ATF I drained, cleaned magnets, new gasket, filter and filled up 3.8L before it overflowed, tilted it a few degrees forward and I added a bit extra. Suppose it wont be fully flushed but once up to temp maybe some will come out or I’ll add more.
Anyway done sealing and fluid changes for now
I know the trans flush can be done in the car by moving the exhaust out of the way - what about some of those o-rings and that line you changed? Can it be done with the trans in the vehicle?
