B7 Rear Differential Styles 01R, 0AR, & 08V - Fluid Change & Capacities

[Denio24]

For lack of information on differentials & for people looking to change their fluid, I have decided to make an informational thread. So let's get started.

It seems that only earlier B7 models carried the 01R and 0AR rear differentials. In my case, I have a 2008 Audi A4 with a 08V rear differential with code HUQ. The fluid capacity for 01R differentials is 1.5 liters of 75w90 fluid, and for 0AR and 08V it is .9 liters and 1 liter respectively. To simplify things, 01R, 0AR, and 08V are all part of the common VAG part number designation, such as "01R"-525-053-G. I believe the difference between these three numbers is the style of the differential housing. Some have the drain plug in different locations, and all have varying fluid capacities. For those looking to fit a JHM Helical LSD differential upgrade in their b7 must have a differential housing that starts with 01R.

Audi also had Final Drive Codes that designated different ratios & flange diameters (75.5mm & 70.7mm) which were designed for different engines (3.2, 1.8, 2.0, as well as diesel engines). It was common to see a 70.7mm flange diameter for 1.8L engines.

01R Diff Cases (1.5 Liters of 75w90):

• ETQ, ETR, ETS, ETT, EUB, EXZ, FUB, GDF, HCC

0AR Diff Cases (.9 Liters of 75w90):

• HNL, HNP, HNQ, HNR, JKN

08V Diff Cases (1 Liter of 75w90):

• HUN, HUP, HUQ

If you don't feel like looking on your differential case for the product number & code, there is a sticker in your spare tire well that designates the code of your rear final drive. Just cross reference above & you're good to go.

If anyone has any questions about changing their rear differential fluid, please let me know! It's also one of the easiest things you will ever do. I recommend a good GL5 oil that is 75w90.

For "lifetime fluids," it is good to change them every 40k mi if you plan on keeping your car.

I myself used Mobil 1 Synthetic 75w90; I am in no way endorsing them - it's just what was cheapest at the time at $7 / Quart. You will also need some sort of transfer pump which will make your job ALOT easier. For my oil change the fill plug was on the drivers side. Remove the fill plug, then remove the drain plug. If you're not that good with a wrench, and you like things torquey-torquey the spec is 45 Nm for the drain and fill plug. Pictures soon to come.

[shahk62]

Some pics the drain plug is on the bottom of the diff while the fill plug is on the right side of it :)


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[shahk62]

Fill plug is at the top and drain plug at the bottom for reference


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[Denio24]

That liqui moly sure is good stuff!

[shahk62]

That liqui moly sure is good stuff!

Stinks so bad though hahaha


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[Avant4me]

Nice information here!

[Flexcj5]

I don't think rear differential matters for the JHM 4:1. The JHM is replacing the center diff at the back of the trans housing. Rear differential is entirely separate.

[Denio24]

I don't think rear differential matters for the JHM 4:1. The JHM is replacing the center diff at the back of the trans housing. Rear differential is entirely separate.

You are correct; little mistake there, post updated!

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