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Discussion Starter · #1 ·
Ill start off by saying, today wasnt fun. I had various fluids in places they should never get.

I set out this morning to do an engine flush and oil change, and then to also replace the fluid in the Haldex and rear diff. Getting the haldex pump off was not easy. It was pretty solidly stuck. (also i should note i have a different haldex system than the ones in the how to videos) I took the little screws off first when it didnt budge. Apparently those are for the electric motor housing. I pulled it back and with a screw driver did a little prying on a plastic piece. I realized what i was doing and stopped. I dont think this caused any harm.

I finally got the AOC pump off. I was trying to find the filter, as it wasnt mentioned in any of the tutorials i watched. I took the three torx screws out of the end of the pump assembly figuring it was inside. Inside there was a bearing plate under neat a flat washer looking piece. Above that was a circular piece with holes in it. Each hole had what i can only describe as a spring loaded cap. All of this fell out of course. I "thought" i put it back together right. But apparently not. I put the pump back on. With the vented piece on the bottom side. There is an indent that looks like it matched the venting piece that would have matched up had i rotated 180 degrees. I dismissed this because the plug wouldnt have reached.

I dont know if there are any resources or diagrams of how the internals of the pump are supposed to look. If there are I would appreciate any links. Also if anyone can see anything i did wrong (besides the obvious) I would be most appreciative.

The AWD system definitely isnt working it just rained and the car spun like crazy under power.
 

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Discussion Starter · #2 ·
Well i fixed it somehow. I took it to my dads shop put it on a lift and disassembled the pump again and very carefully put it back together. There aren't that many parts. A motor shaft in the middle. A bottom bearing plate that has a bearing grove, a bearing set (that was slightly bent) Another bearing plate. A weird round piece with holes in both sides. On the bottom side there were caps that were spring loaded. This pressed against the top bearing plate. Above this was the top of the pump that screwed on. I cleaned everything and carefully re-assembled it. I placed a bit of grease on the bearings, mainly to hold them in place. Once the pump was back together i tested it with a 12 volt source and it worked. I reinstalled the pump on the car, added fluid back in. Since the car was on a lift, I left the parking brake on and put it in gear. It stopped the front tires from spinning, even with a little power applied. Driving since then has proven that it works as expected. Oddly I noticed that my pump and connectors had the audi VWAG logo on them.


My advice is to not mess with the AOC pump, remove it, and leave it. Turns out the filter is above the drive shaft, and almost inaccessible from what i could see. Having the car on a lift did allow me to change my angle gear oil.
 

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Good that you fixed it as replacement pumps are quite expensive.
Changed the fluid in my 2015.5 Gen 5 Haldex today. No issues luckily.
 

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My advice is to not mess with the AOC pump, remove it, and leave it. Turns out the filter is above the drive shaft, and almost inaccessible from what i could see. Having the car on a lift did allow me to change my angle gear oil.
FWIW, an index wrench + 48mm socket will give you much easier access to the filter; CTA makes a specialized tool if you don't have a 48mm socket.
That is nothing even remotely like what works for the Haldex Gen 4/5 filters on our cars. The filter on our cars is held in place with two Allen head screws. That tool is only useful for Haldex Gen 2 systems, which haven't been in broad use since around 2006 or 2007.

Here's what servicing the Gen 4 Haldex on our cars looks like, note the absence of any 48mm sockets:
https://youtu.be/uZNC06Z7imQ

And here's a Haldex Gen 5 service, again, note the lack of 48mm sockets:
https://youtu.be/R4mb-e-3R7M
 
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