Rear Differential Fluid Change

[audivoodoo]

DIY: Rear Differential Fluid Change


TOOLS, PARTS, MATERIALS:

~ 3/8 Socket Wrench
~ 3/8 6” Socket Extension
~ 3/8 Swivel-Head Socket Extension
~ 3/8 10mm Hex-Head Socket
~ 3/8 Torque Wrench
~ Fluid Transfer Hand Pump ( I used a cheap 6$ one from Autozone, but something like a Mityvac will save you a few hand cramps)
~ 1.9 Quarts of you favorite 75w90 Gear Oil (Here is a good FAQ to choose one. Thank you dparm)
~ A Lift or Jack and Jack Stands
~ Oil Catch Can.
~ Safety Glasses
~ 2 Beer’s






Note: The following procedure is intended to be a guide only, and was accomplished on a ’04 B6 S4. If followed improperly, damage to you or your property is possible. I take no responsibility for your undertaking of this procedure. Accomplish at your own risk. Remember, Safety first.

DIFFICULTY:

This is extremely easy and can be accomplished by just about anyone who knows what the tools and parts listed above are. Total time for me with a lift was 20 Min. It will take a bit longer if you use a jack and jack stands or wait for the car to cool a little (you do want the oil to be warm thou).


PROCEDURE:

1. Disconnect the battery.
2. Beer sip
3. Set the E-Brake, block the front tires, lift the rear of the car and place on jack stands, remove jack. (Never work under a car supported only by a jack) Alternately and preferably lift the car with a lift.
4. Beer sip
5. Place oil catch can under the rear differential.
6. Beer sip
7. With a 10mm Hex-Head Socket attached to a swivel and 6” extension, remove the 10mm Hex-Head nut that is towards the top of the right hand side of the differential.
8. 
9. Beer sip
10. Now remove the 10mm Hex-Head nut on the bottom of the differential and drain all of the old oil.
11. 
12. New beer, beer sip
13. Reinstall the bottom nut and torque to 30ft lbs (40Nm) (This is what it was for my old car and couldn’t find the torque spec for the S4. will correct if someone posts it up)
14. Beer sip
15. Install pump on the quart of oil, install hose into the hole from the removed nut on the top right and pump away.
16. 
17. Beer sip
18. Add 1.9 Qts of oil, reinstall 10mm nut and torque to 30ft lbs (40Nm) and wipe up any excess drips.
19. Beer sip
20. Drop the car, reconnect the battery.
21. Finish beer.
22. Properly dispose of your oil and beer cans. Have a good day

[c13h18n2]

Sweet! Thanks! Question, though. Does it have to be Coors Light?

[04 S4]

lol at the beer.

c13h18n2 - if you need a hand, I just did this friday lol

[dparm]

Something to add here: the car needs to be level when you do this or you will not drain/fill the proper amounts. I suggest getting it on a lift if you can; otherwise, take the car off the jackstands and let it rest on its tires while the fluid is draining. You will want to pump in the fluid while it's level too, so either get it on the lift or four jackstands, or get a longer hose so the car can be on the ground.

You should refill it so the fluid is just below the "fill" hole, if I recall correctly. It's technically 4.1 pints = 2.05 qt = 1.94 L if you have a manual trans, and 3.2 pints = 1.6 qt = 1.51 L if you have the auto trans. I might be off a bit on those figures since I don't have the factory service manual, though if you fill to the very bottom of that hole it should be the proper amount. Hopefully someone can confirm.

[masaraksh]

I did this today.

One tip I would recommend is to remove the axle shield on the rear pass side. It makes getting at the fill plug MUCH easier. The shield is held on by 3 bolts that are very easily removed with a 6mm hex socket.

[SurferD]

Another tip if you're using Coors Light is to make sure the mountains are blue for optimum temperature as audivoodoo did.
Good write-up.

[dparm]

Better yet, drink good beer.

[jeffrey146]

Didn't drink the beer because I had to drive. However it all worked great for me.

[B6A4Dave]

Semi-Necro bump.

Besides the confidence of knowing that you did it and it doesn't have to be done again. Were there any noticeable differences from before to after? Was your diff making noise prior to the service?

[m-ys4]

when should this be done? how many km/years?

[jaehoppa]

is this for the s4? IIRC RS4 requires 0.9L?

[SprintBlueWorld]

Anyone know if the oem drain plug is magnetic?

[jakeoboy67]

Anyone know if the oem drain plug is magnetic?

I dont recall mine being magnetic or anything(metal shavings) being stuck to it.

[daniel B6 1.8t]

Just to ,ake sure the center and rear diff for a 5 speed auto TIP use the same 75w-90 oil? I just realized mine hasnt been done and it feels like little slips and heavy when moving... Yes the TRANSMISSION has been changed just 3months old with AUDI'S OEM oil. Just wanna make sure before i buy anything before hand. Thanks

[Fourpoint282]

DIY: Rear Differential Fluid Change


TOOLS, PARTS, MATERIALS:

~ 3/8 Socket Wrench
~ 3/8 6” Socket Extension
~ 3/8 Swivel-Head Socket Extension
~ 3/8 10mm Hex-Head Socket
~ 3/8 Torque Wrench
~ Fluid Transfer Hand Pump ( I used a cheap 6$ one from Autozone, but something like a Mityvac will save you a few hand cramps)
~ 1.9 Quarts of you favorite 75w90 Gear Oil (Here is a good FAQ to choose one. Thank you dparm)
~ A Lift or Jack and Jack Stands
~ Oil Catch Can.
~ Safety Glasses
~ 2 Beer’s






Note: The following procedure is intended to be a guide only, and was accomplished on a ’04 B6 S4. If followed improperly, damage to you or your property is possible. I take no responsibility for your undertaking of this procedure. Accomplish at your own risk. Remember, Safety first.

DIFFICULTY:

This is extremely easy and can be accomplished by just about anyone who knows what the tools and parts listed above are. Total time for me with a lift was 20 Min. It will take a bit longer if you use a jack and jack stands or wait for the car to cool a little (you do want the oil to be warm thou).


PROCEDURE:

1. Disconnect the battery.
2. Beer sip
3. Set the E-Brake, block the front tires, lift the rear of the car and place on jack stands, remove jack. (Never work under a car supported only by a jack) Alternately and preferably lift the car with a lift.
4. Beer sip
5. Place oil catch can under the rear differential.
6. Beer sip
7. With a 10mm Hex-Head Socket attached to a swivel and 6” extension, remove the 10mm Hex-Head nut that is towards the top of the right hand side of the differential.
8. 
9. Beer sip
10. Now remove the 10mm Hex-Head nut on the bottom of the differential and drain all of the old oil.
11. 
12. New beer, beer sip
13. Reinstall the bottom nut and torque to 30ft lbs (40Nm) (This is what it was for my old car and couldn’t find the torque spec for the S4. will correct if someone posts it up)
14. Beer sip
15. Install pump on the quart of oil, install hose into the hole from the removed nut on the top right and pump away.
16. 
17. Beer sip
18. Add 1.9 Qts of oil, reinstall 10mm nut and torque to 30ft lbs (40Nm) and wipe up any excess drips.
19. Beer sip
20. Drop the car, reconnect the battery.
21. Finish beer.
22. Properly dispose of your oil and beer cans. Have a good day

Nice write up. How often should rear diff fluid be changed?


Sent from my iPad using Audizine

[JayDog747]

Gear oil should be changed every 50k.

[DPDISXR4Ti]

Bumping this thread as it seems to be the one with the most details on changing the rear diff fluid. I don't currently have a hand pump, so wondering if there's clearance to get a squeeze bottle in there - yes, no, maybe???

Otherwise I'll just get a hand-pump. Suggestions on which one to get? Is there a Mity-Vac attachment?

[DPDISXR4Ti]

Did this job today. I went ahead and got a hand pump - I was thankful I did so as it made things go rather easily. Couple things...

1) Definitely make sure you remove the FILL plug first. I needed a cheater bar on my breaker bar - I was worried I had broken the socket once it finally moved. The drain plug came out much easier for some reason.

2) Definitely remove the CVJ boot shield (3 Allen head bolts) to get easier access to the fill plug.

3) I had evidence of an oil leak on the left side of the differential. The CVJ boot shield was caked in exhaust-heated goop. I'll have to monitor this with the new fluid installed.

4) Fluid capacity was just under two quarts. I just kept pumping it in until the fluid started coming out the fill hole.

[Atomic Avant]

Great write up.

I changed mine a few weeks ago with no issues, I had lots of access to the fill and drain plugs without removing anything extra.

I should have check on my cheap hand pump before I drained the diff. Its seals basically fell apart. Thankfully the pet store was still open so I could get another pump. (Every hardware/automotive store closed at 5pm on Sunday. It was 530 when I realized I needed a new pump.