Differential Fluid Change

[jfo]

I changed the rear and front differential fluid today. The rear is easy and the front a bit more work. The center however is more challenging since the drain plug is on the bottom and covered by the transmission crossbeam. The fill plug on the side is also more difficult to access with limited space between the tunnel and differential. Has anyone done the centre? I may try my oil extractor and see how much I can suck out the fill hole.
My new Quick Jack made this job immensely easier than jack stands and ramps. Lot's of room to work comfortably on the creeper, position lighting, find tools, reach around obstacles, and far less claustrophobic!

[mecg]

Thinking about doing this. What exactly did you use for lube in the differentials?

[jfo]

It calls for 75W-90, GL5 gear oil. I used Castrol Synthetic but any similar oil will do.

[A4x]

Is that on the 8 speed tip? Is the front diff part of the transmission housing, but uses separate oil? I ssume it is internally sealed off somehow from the rest of the transmission.

What quantity of oil did the front and rear take?

I plan on doing this next spring.

[leftlanecruiser]

Also curious about this. According to my shop manual for my 8 speed tip, the front and rear difs have a different oil than the center dif.

For 8spd 0BK/0BL Transmission:
Initial Fill(trans) - 9.0L(9.5 qt.) - G060162A2
Refill(trans) - 3.6L-4.0L (3.8qt.-4.2qt.) - G060162A2
Front Final Drive - 1.0L (1.1qt.) - G052145S2
Transfer Case - 1.0L (1.1qt.) - G055145A2
Rear Final Drive - 1.0L (1.1qt.) - G052145S2

So far i have found equivalent fluids for the front and rear difs, but not the center dif (transfer case). I can only find a VW/AUdi part number on that oil. Also, when i purchased my transmission fluid i bought oem since i would not be able to drain it completely. If i used a different oil for the transmission then i would have different oil mixing which would be bad so i didnt want to risk it.

[jfo]

Is that on the 8 speed tip? Is the front diff part of the transmission housing, but uses separate oil? I ssume it is internally sealed off somehow from the rest of the transmission.

What quantity of oil did the front and rear take?

I plan on doing this next spring.

Yes, the 8 speed Tip, and the front diff is part of it but has it's own gear oil. Drive shafts exit the centre diff or transfer case with one going to the rear and a shorter one that runs along the side of the transmission going to the front diff. The passenger side axle is attached to it and this where the fill plug is located. The smaller drain plug is on the bottom.
On the 2011 the rear diff takes 1.1L and the front and centre take 1.0L. The 2009 rear is different and takes 0.9L. I don't know about other model years.

[jfo]

Also curious about this. According to my shop manual for my 8 speed tip, the front and rear difs have a different oil than the center dif.

For 8spd 0BK/0BL Transmission:
Initial Fill(trans) - 9.0L(9.5 qt.) - G060162A2
Refill(trans) - 3.6L-4.0L (3.8qt.-4.2qt.) - G060162A2
Front Final Drive - 1.0L (1.1qt.) - G052145S2
Transfer Case - 1.0L (1.1qt.) - G055145A2
Rear Final Drive - 1.0L (1.1qt.) - G052145S2

So far i have found equivalent fluids for the front and rear difs, but not the center dif (transfer case). I can only find a VW/AUdi part number on that oil. Also, when i purchased my transmission fluid i bought oem since i would not be able to drain it completely. If i used a different oil for the transmission then i would have different oil mixing which would be bad so i didnt want to risk it.

I've done a lot of searching about the diff oils and haven't found a definitive answer about the need for the G055 version of the gear oil in the 8 speed centre diff, when doing a drain and fill. It is the same oil as the G052 version but with 3% Sturaco friction modifer added. It costs $80 to $100/litre compared to $18-20 for the G052. I'm OK with the outrageous price if it's indeed needed. I've come across forum info quoting ZF manuals that say "The STURACO FM 1992 additive is only needed after renewal (exchange) of the Torsen differential.", and not required when topping up. Apparently the additive clings to the metal and only needs to be added to a new or rebuilt differential. This info however came from a 6 speed Tip manual and I haven't yet confirmed if it is carried over to the 8 speed. The 8 speed does have the same set up and does use the same Sturaco additive, so it's likely the same. I'm not ready to do the centre yet , so I'll try communicating with ZF Tech Support for clarification.

[A4x]

Also curious about this. According to my shop manual for my 8 speed tip, the front and rear difs have a different oil than the center dif.

For 8spd 0BK/0BL Transmission:
Initial Fill(trans) - 9.0L(9.5 qt.) - G060162A2
Refill(trans) - 3.6L-4.0L (3.8qt.-4.2qt.) - G060162A2
Front Final Drive - 1.0L (1.1qt.) - G052145S2
Transfer Case - 1.0L (1.1qt.) - G055145A2
Rear Final Drive - 1.0L (1.1qt.) - G052145S2

So far i have found equivalent fluids for the front and rear difs, but not the center dif (transfer case). I can only find a VW/AUdi part number on that oil. Also, when i purchased my transmission fluid i bought oem since i would not be able to drain it completely. If i used a different oil for the transmission then i would have different oil mixing which would be bad so i didnt want to risk it.

Yes, the 8 speed Tip, and the front diff is part of it but has it's own gear oil. Drive shafts exit the centre diff or transfer case with one going to the rear and a shorter one that runs along the side of the transmission going to the front diff. The passenger side axle is attached to it and this where the fill plug is located. The smaller drain plug is on the bottom.
On the 2011 the rear diff takes 1.1L and the front and centre take 1.0L. The 2009 rear is different and takes 0.9L. I don't know about other model years.

Great info Thanks.

Are you sure it is 1.1L or should it be 1.1 qt = 1.0L like leftlanecruiser posted? Either way, I think you just fill until it starts to come out of the fill plug?

In your opinion if I have shop do the front and rear diff, what should they charge me assuming I provide the oil? 1 hour of labor? I'd love to do it myself, but don't have a lift and don't want to crawl under on jackstands. Bilstein B12s don't help with that either haha.

[jfo]

Great info Thanks.

Are you sure it is 1.1L or should it be 1.1 qt = 1.0L like leftlanecruiser posted? Either way, I think you just fill until it starts to come out of the fill plug?

In your opinion if I have shop do the front and rear diff, what should they charge me assuming I provide the oil? 1 hour of labor? I'd love to do it myself, but don't have a lift and don't want to crawl under on jackstands. Bilstein B12s don't help with that either haha.

The erWin manual shows 1.1 L but also 1.0 qt conversion for that particular entry. Other figures in the doc show a 1.1L conversion as 1.2 qt, which is correct. I suspect the 1.0 qt is a typo. But you are right, just fill until it starts to drip out the fill hole.
Without my QuickJack, I wouldn't want to spend that much time under jack stands either. I have had it on ramps at the front and stands at the back, but 4 fully extended stands makes me nervous.
I would say 1-1.5 hours for both at a shop. I have the Euro Code Alu Kreuz frame brace which makes draining a bit tricky and messy. It may be an easy drain with the OEM brace, since the open area is larger.

[mecg]

Did you put new plugs back into the diffs, as the manual says you should? If so, where did you get them and how $ were they?

[s4baby]

Did you put new plugs back into the diffs, as the manual says you should? If so, where did you get them and how $ were they?

https://www.ecstuning.com/Audi-B8_A4.../Differential/

[mecg]

^^ Thanks!

[jfo]

https://www.ecstuning.com/Audi-B8_A4.../Differential/

The drain plug for the front and centre is smaller...M12. The fill plugs are M18.

01V409057A

[leftlanecruiser]

I did make a typo, the volume on the rear dif should be 1.1L (1.1qt). I'm not sure how 1.0L=1.1qt and 1.1L=1.1qt but thats what the erwin manual says.