Hi all.

Noticed there wasn't much on the forums for this for the A4 in particular so I'll just do a quick write up of the procedure. Just a disclaimer that I am in no way responsible for any damage caused or injuries sustained in doing this.

Difficulty: Easy. Should take no longer than 45 minutes.

Tools needed.

3/8 inch socket wrench
150mm or 6 inch extension.
2x 1L bottles of fluid ( I used Liqui Moly HOCHLEISTUNGS-GETRIEBEOL (GL4+) 75W-90)
10mm Allen/Hex bit
Torque Wrench
Drain Pan
Jack & jack stands (preferred) or ramps
Fluid pump (I had a 1L fluid transfer pump)
Scotch (for after)
Gloves - exhaust burns hurt.

(Tool setup. I thought I needed a universal joint at the end but turns out not required )


Step 1: On a warm car (to get the fluid to operating temp) Raise the car up. Ideally jacking the car up on all 4 corners to keep it level is ideal. But ramps can be used if you're feeling lazy (I was)

Step 2:

Locate the diff under the car looking out for the 10mm hex head drain and fill plugs. Just taken 3 pics showing sorta how to get there. It's in front of the sway bar with the drain plug being located on the underside of the diff and the fill plug slightly forward of the drain plug but towards the top of the right hand side of the diff. (Third pic shows both drain and fill plugs)



Step 3: Using the socket wrench and extension Proceed to undo the fill plug. ALWAYS undo the fill plug first as otherwise if you cannot do this and you drain fluid your car will not be drive able at all. The fill plug was on pretty tight and took some decent force to get loose so just keep that in mind if you feel like it's just not coming off. Once it's off clean the plug of any metal / gunk stick to it. It's a pretty damn fat plug.

Step 4: with a drain pan underneath undo the drain plug using the socket wrench without the extension. Once the bolt is loose undo it with your fingers to prevent a bunch of oil going on your tools. Fluid will take a few minutes to drain completely.

Step 5 (optional): As I was on ramps my diff wasn't level so I knew I hadn't gotten all the fluid out - so to flush the fluid I reinstalled the drain plug and hand tightened before putting some of the new fluid (about 100ml) into the diff and then draining again. Sorta like a mini flush so to speak.

Step 6: Clean and Reinstall drain plug or use a new one (ideal) and tighten to 40NM using a torque wrench.

Step 7: Fill fluid with your pump (my hands were pretty tired after this) until fluid just begins to leak out of the fill hole. (Keep your drain pan underneath. It will take just over a litre of fluid (1.1L )

Step 8: Reinstall clean or new fill plug and tighten to 40NM.

Step 9: Clean diff with a rag of any oil before lowering the car and going for a drive. Inspect for any leaks after you come back and you're done

Hope you find this useful!

If you think something should be done differently let me know and I'll edit accordingly.







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