Was it replaced with a new or refurbished unit?

 

Work order stated part: ocq-525-010-s which shows up online as new.

 

So, as you said technically the replacement is out of warranty. Be glad for anything they willingly do since legally they do not have to help at all. Be glad you don’t have a TD1 flag as well.

 

If the dealer installed it, they probably filled it incorrectly. Diff fluid in haldex unit or vice versa. Wouldn’t be the first time “Certified Tech” ****s something up…..


Sent from my iPhone using Tapatalk

 

Who has been doing these fluid changes? You? Same tech every time?

 

Dealer did during the 30k service. A very reputable and dealer-known VW/Audi specialist shop did the others.

This is something the service rep mentioned. Since VW is "all about customer loyalty", service history with the dealer would be more in my favor. But we all know how dealer service is, as mentioned above.

 

The diff fluid in Haldex and Haldex fluid in diff phenomena is well documented. Moreover, if the pump screen isn't being cleaned, you aren't accomplishing much with your fluid changes.

 

.....Moreover, if the pump screen isn't being cleaned, you aren't accomplishing much with your fluid changes.....

So, what is the percentage of flow restriction while in operation with a screen that was not cleaned? With this percentage restriction, how is the unit function effected?

 

^^this

Sent from my SM-N975U using Tapatalk

 

Validated. I've explicitly requested to have the screen cleaned when serviced. The service done in March, 10k after the new haldex was installed, stated that there was heavy amount of clutch material in the screen.

My assumption is that it was either a bad unit that was installed by the dealer, or the tech mixed up the fluids upon install.

 

My knowledge of exactly how the haldex works isn't the best, but I thought a failed haldex makes the car act like a FWD car? How does a failed haldex cause the rear to completely lock up?

 

...How does a failed haldex cause the rear to completely lock up?....

Others have reported this characteristic of the mixing of the fluids. There are numerous ways for the unit to fail but lockup seems to be the way with the use of the wrong fluid.

 

Update in OP.

 

I think DarkArrow is onto something here.

 

The differential is the issue. The service rep stated the whole differential assembly will be replaced, stating that the haldex is part of it. I asked him about lubrication procedure during installation, and he stated, "it either comes boxed filled, or added during installation. Either way, it's the same fluid, not two different fluids".

 

I think there's your answer...

It's not two different fluids. My guess is that during your last Haldex service, they put Haldex fluid in the rear differential and the rest is history.

 

If you have any of the fluids (Haldex or differential) left in your possession, I would send them to Blackstone Labs for identification and analysis. If not, drain what's in there now and send those samples in. See if they can suss out if it's an improper fluid issue.

Sent from my SM-G973U using Tapatalk

 

Thanks, ginger. I've been looking for documentation that explicitly states two different lubricants. I confirmed this with the shop I go to for service. Going to use this to air some more grievances with the dealer today. Wish me luck.

 

something to note: at one point VW had the wrong fluid listed in erWIN. I actually had a long email exchange back and forth with one of the tech guys who kept telling me it was correct. Finally, they reached one of the engineers who explained that yes, the documentation was incorrect. The shop may have been using a fluid capacity chart with the incorrect info--may not even be the tech's fault...

 

Update in OP.

 

You have zero chance of getting any reliable information handed to you by a dealership. At this point the best you can do is document everything they've said, get under your car and mark your diff with some invisible marker in a few places, get it replaced, demand the old unit back, and split the casing open to see what fluid residue is in there and how exactly it failed. Preferably do the last item in the dealer's parking lot. If it turns out this thing that talks, walks, quacks, and smells like a duck is in fact a duck, maybe you can get some support from VWoA.

 

Hey if you need just the differential I have one from my 2016 R. We can work something out.

But that diff shouldn't fail like that. Sounds like faulty maintenance via different fluids in the diff vs haldex. I beat my car quiet frequently through corners and no issues here on a 80k mile R with 400hp daily driven.

 

A little late to the party, but could something be miss aligned? Say the driveshaft, that is putting undo torque or pressure on other components. I have seen 8n the past this type of failure happen on a truck that the pinion angle was a couple of degrees off and the left side of the rear axle housing had shifted in the spring mount due to hard launches from dirt to pavement. The result was a catastrophic failure of the diff. The thing literally blew up inside the housing.
maybe something as simple as a mount or a broken bolt. Just spitballing.

 

The result was a catastrophic failure of the diff. The thing literally blew up inside the housing.

I literally had the rear diff on my c10 do this two months ago, but the pinion angle was good. It was just from metal fatigue and rust on the gears from sitting around on a farm.