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Discussion Starter · #1 ·
I thought I was going to be able to remove the Hladex pump motor without removing the drive shaft, but now have discovered that I have a Haldex 3, which will indeed call for removing it. Is this a reasonably straight forward or easy thing to do? I bought all the oil, transfer pump, hose, filters etc for the job; I hate the thought of taking it to the dealer now. Can anyone post a sort of instructional on dropping it?
Thanks!
John D.
 

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By transfer pump, do you mean you're replacing the haldex pump or just that you're using a pump to replace the fluid? If you're not removing the pump then the rest can be done with the prop shaft in place. Source: I have gen III and I've replaced oil and filter on it.
 

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Discussion Starter · #3 ·
By transfer pump, do you mean you're replacing the haldex pump or just that you're using a pump to replace the fluid? If you're not removing the pump then the rest can be done with the prop shaft in place. Source: I have gen III and I've replaced oil and filter on it.
I was planning on changing the filter and oil, but also on removing the motor to give it a cleaning out. The transfer pump I was referring to is the small 12V pump I bought to drain the oil from the haldex and angle drive as well.
I confess that my source of information has been the Youtube videos by volvoseden (
), who performs this service on a Haldex 4 XC90. He mentions that his method will not work on the haldex 3, and I can see why, as the motor housing is a different configuration than on earlier versions. On the Haldex 3 car, the larger style motor canister is too close to the drive shaft flange to remove the motor without dropping the drive shaft.
 

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It sounds like you bought a new pump to replace the current one, in which case the rear of the prop shaft will have to drop. I managed to do it without removing the exhaust, but I'd recommend getting the exhaust out of the way. You can wiggle the back of the shaft free without completely removing it, but in hindsight it really isn't that hard to pull the whole thing.

There's 6 bolts holding the rear of the prop shaft to the AOC. You also will have to remove the cup that connects the prop shaft to the AOC unit. That's held on by a single shallow nut, and the nut is a pain to remove. Go to the hardware store and buy a couple bolts with the same thread pattern that you don't care about bending. Then use a small bar or something between the nuts to brace the cup and keep it from turning. A 3/8 impact wrench on low impact is perfect for removing the nut, but I think a 1/2 would squeeze in the tunnel too. The nut is held on with what I think is red loctite.

Pull the prop shaft, then the cup, then you can remove the pump. When you reinstall the shaft, blue loctite the bolts back in place.

And finally, I'll try to dig up my thread from about a year or so ago about this. It has pictures and such.

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Discussion Starter · #5 ·
Thanks, but I think I may have presented a confusing post. The pump I bought is not a replacement pump for the AOC, it is a cheap 12V fluid pump that I was going to use to drain the angle drive when I serviced both it and the haldex. The only reason I wanted to remove the actual haldex pump was in order to clean it out, not to replace it. Also, in order to fully drain the oil from the AOC/Haldex, is it not necessary to either a) remove the pump and let it drain, or b) suck the oil out of the filter housing? Someone please help me out here.
JD
 

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Thanks, but I think I may have presented a confusing post. The pump I bought is not a replacement pump for the AOC, it is a cheap 12V fluid pump that I was going to use to drain the angle drive when I serviced both it and the haldex. The only reason I wanted to remove the actual haldex pump was in order to clean it out, not to replace it. Also, in order to fully drain the oil from the AOC/Haldex, is it not necessary to either a) remove the pump and let it drain, or b) suck the oil out of the filter housing? Someone please help me out here.
JD
Ah, I see. You can pull the pump out part way to drain all the fluid. I'd recommend squirting a little fluid on the pump screen to try and dislodge any particles on it. Then flush that cavity. You can pull all of the fluid out of the filter cavity just by pulling the filter out. It sits horizontally. Then clean the sludge out of there with a microfiber towel. It is very important that the filter housing be completely clean.

So you don't need to suck any fluid out of the AOC unit. There will be a tiny bit of fluid remaining, but there's no way you could get that out without removing the whole AOC unit. Trust me, I've been through that fiasco. And whatever you do, do NOT try to remove the brass "screw" with the hex head. You mess that up, it's time to buy a new unit. That "screw" is the accumulator for the whole thing

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Discussion Starter · #8 ·
Thanks for that. It sounds as though this has been a frequently discussed item.
After reading and viewing the other posts, it appears that I will pull the filter unit to drain the fluid, replace the filter and cap, then remove the bolts from the pump and pull it forward just enough to let what fluid remains drain from that location.
If there is sufficient space, I will attempt to spray an evaporative cleaning fluid (such as brake cleaner) to try to dislodge any crud that may have accumulated on the small obscured pump filter screen. I will likely let it sit for 24 hours before buttoning it back up and refilling with oil, just so that the cleaner evaporates, and anything that is going to drain out does so.
This car, by the way, had 149,000 km on it (about 95K miles) and this and the angle drive and transmission oil change are purely preventative measures, as the car seems to run just fine. This is a new-to-me unit, but dealer records show these services have never been performed on this car.
John D.
 

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I got the rear of the prop shaft apart by using a chisel and striking it at a 45 degree angle, first one side and then the other by turning it 180 degrees. The trick is using a sharp chisel which I achieved by running it on the belt sander. 15/16 nut came off with the impact gun after the exhaust was lowered enough to make room.

The pump I have has the wire bundle coming out the side of the cover. Has anybody pulled that cover off to get inside the motor and if so how did you do it? This pump is quite different from the one in the youtube video. I think I will just put 12V to it and see if it turns and if so reassemble it. I wonder if polarity is important? Although the screen was clean I did find some crud around the threads of one of the screws so maybe a passage was plugged.
 

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I wonder why they don't sell just the filter element and an O-ring instead of with the aluminum cover and the extra screws.

Car seems good with AWD working now. It was fixed on warranty some time before 80k kms and now serviced at 206k kms so at least 120k kms since last service. 80k kms or 50k miles seems to me like a good interval.
 

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I wonder why they don't sell just the filter element and an O-ring instead of with the aluminum cover and the extra screws.
Easy enough to cross reference this part with Ford and Range Rover, maybe you'll find just the filter. See link for another reference to Ford- http://forums.swedespeed.com/showthread.php?147720-AOC-Haldex-and-rear-diff-fluid-change-complete

Cover was modified with a more solid design including the fins and a plastic rear retainer a few years back, many older cars had just a simple stamped metal filter cover installed by the manufacturer.

Makes perfect sense to source the filter itself (if you can find), especially after you've done the first filter change with the new cover.
 
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