B7 Rear Differential

**Crasher** · 26-10-2016,04:56 PM

Even the VAG system can't be sure what it has, it narrows it down to an 01R series ETR code or an 0AR series HNQ code, you MUST get the code (ETR or HNQ) off of the diff in the car. Both of these diffs were only used in the A4q from 2004>2008 with the BFB engine and GJW gearbox. A new unit from Audi is £4301.48, they do not offer a recon

**Dalmation11** · 27-10-2016,09:36 AM

Originally Posted by Crasher

Even the VAG system can't be sure what it has, it narrows it down to an 01R series ETR code or an 0AR series HNQ code, you MUST get the code (ETR or HNQ) off of the diff in the car. Both of these diffs were only used in the A4q from 2004>2008 with the BFB engine and GJW gearbox. A new unit from Audi is £4301.48, they do not offer a recon

Thanks Crasher,

thats a lot more information than I've got so far, it gives me more to go on.

Thanks,

Nick

**Dalmation11** · 27-10-2016,09:40 AM

Just had a look and I've got OAR 525053A, HU 55051-0 and A1s19cu3 stamped on it. Do I need to match these numbers exactly when finding a replacement ?

Thanks again,

Nick

**Crasher** · 27-10-2016,01:23 PM

The first number does tell us it is the 0AR series so the code must be HNQ but the full number is just a casting number for the case, it is meaningless as it is not a number you can buy and there could be any one of half a dozen different ratios in there. The three digit code you have not yet found is the key.

HU etc, no idea.

A1s etc is the composition of the aluminium alloy it is made of.

**Dalmation11** · 01-11-2016,01:55 PM

Update, I went to Audi main dealers with my V5, they looked up the chassis number and told me they could get one for £4300 but couldn't help me with any diff. codes and were really unhelpful, all they said was it was an ETR ?

I have found HNQ 837 stamped on the casing, is this all I need to find a used one, I don't want to buy the wrong one ?

Crasher, thanks again for your help.

Nick

**Crasher** · 02-11-2016,11:24 AM

HNQ 837 is the unit code and means it was made on the 08/03/2007 and the car was built on 22/03/2007, I don't know how they can be sure it is an ETR as there is nothing on the PR data to differentiate between the two and you found 0AR and HNQ on the case which identifies the unit type very clearly, the system ETKA under what is called FI suggestion clearly indicates it has both which obviously isn't possible and the workshop data system ELSA win shows that it could have ETR or HNQ but it is very specific in that your car has a BFB engine and GJW transmission, type number 8ED0A9 can have either ETR or HNQ. The only way you can identify what the unit your car has is by finding the code stamping which you have now found. As the unit is an HNQ, according to ETKA it means you can also fit an MPB and this is what you would get if you bought a new Audi unit, part number 0AR 500 043 S and these retail at £4301.48

**zollaf** · 02-11-2016,11:30 AM

£4300, might as well buy 2 and have a spare.

**rowdy-999** · 02-11-2016,11:47 AM

You would think manufacturers would decrease the price of parts as cars get older. Who would nearly spend the value of a car on one part alone?
OP- hope you get it sorted soon.

**Dalmation11** · 02-11-2016,12:22 PM

Thanks for the info Crasher, you're a star. I'm looking on eBay and there are quite a few but there are so many variations, I don't want to buy one that doesn't fit. If I look for one with an OAR and HNQ code it should fit ? I'm finding this really confusing, I love the car, it's in mint condition but can't afford to spend thousands on it. A used one is my only option.

Nick

**Crasher** · 02-11-2016,01:40 PM

I doubt anyone will list the series of the unit, the 0AR part, unless they were a sad **** git like me, I would not expect any more info than the version code which is the HNQ bit or possibly the original units part number, 0AR 500 043 E. Some are asking stupid money for used units as they know how much new ones are.

0AR500043E | eBay