What cars have the same haldex?
02-28-2019, 04:39 AM
#1
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What cars have the same haldex?
I have a 2002 Audi TT 225 Quattro roadster and the haldex has started to go and I’m looking to get one off a part yard car. What cars should I look for to get one and is there anything I should know about removal/instillation and what price they might charge?
Thanks in advance
Thanks in advance
02-28-2019, 05:37 PM
#2
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You can never go wrong with the same model year/transmission and engine code vehicles. For R&R instructions, follow the Service manual procedure. Especially when it comes to the half=shafts and driveshaft disconnection.
03-03-2019, 04:14 PM
#3
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I have a 2002 Audi TT 225 Quattro roadster and the haldex has started to go and I’m looking to get one off a part yard car. What cars should I look for to get one and is there anything I should know about removal/instillation and what price they might charge?
Thanks in advance
Thanks in advance
03-04-2019, 04:45 AM
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I got the car 2 years ago and it has always had noise from the rear but it’s just getting to the point where it’s too much for me. It’s a roadster and the noise is a whine/hum and it gets worse with speed, when I’m going 55mph+ the noise from the rear is louder than the wind noise (with the top up). The noise stops for about a half a second whenever I get on or off the throttle. It makes the noise regardless of if it’s in gear and engine rpm. When I pulled the haldex fuse the noise went away but I put it back because I didn’t want to risk further damaging the haldex/diff. I just replaced the haldex fluid and the diff fluid and the noise is the same (both were pretty black but didn’t have any particles, also after filling the haldex I checked the level and it is a bit low , about 1/2 inch below the bottom of the inspect port, should I order another tube of fluid to top it off?). It also makes a terrible groan/grrr noise between 10-5 mph.
03-04-2019, 09:53 AM
#6
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I got the car 2 years ago and it has always had noise from the rear but it’s just getting to the point where it’s too much for me. It’s a roadster and the noise is a whine/hum and it gets worse with speed, when I’m going 55mph+ the noise from the rear is louder than the wind noise (with the top up). The noise stops for about a half a second whenever I get on or off the throttle. It makes the noise regardless of if it’s in gear and engine rpm. When I pulled the haldex fuse the noise went away but I put it back because I didn’t want to risk further damaging the haldex/diff. I just replaced the haldex fluid and the diff fluid and the noise is the same (both were pretty black but didn’t have any particles, also after filling the haldex I checked the level and it is a bit low , about 1/2 inch below the bottom of the inspect port, should I order another tube of fluid to top it off?). It also makes a terrible groan/grrr noise between 10-5 mph.
Since the pulling of the fuse corrected the issue, it's definitely Haldex-related. The issue you're having could potentially be a controller problem, but the whining/groaning makes me feel as though there may be an issue with the clutch plates or gears in the differential. Believe it or not these diffs are known to be very robust so when this happens it's usually because a previous owner ran the car improperly on a dyno or something similar. For example, my car has nearly 200k miles but still has its original Haldex/diff - my AWD is out right now because my cargo pump failed recently.
If you have VCDS, it may also be worth checking out your ABS and ESP systems for codes related to wheel speed sensors or the like. Faulty sensors may not throw the lights on but those systems are all tied into the operation of the Haldex.
03-05-2019, 06:21 AM
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No codes in vcds. Would I be able to tell if there was a problem with the haldex or diff based off the oil. Both had their fluid replaced just over a week ago and both where long overdue. The diff had no metal in the oil but there was a small amount of shavings on the cap but nothing much and no big pieces and with the condition of the oil it might have been the original oil or at least had not been changed in a very long time. The haldex fluid was also pretty dark and no light would shine through it whatsoever when I put a flashlight to it when it was in a cup but there where no visible particles in it. I let it sit for a couple of days to see if anything would settle out of it but nothing did and I even put a magnet in it for 3 days to see if there was metal in it but there was nothing.
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03-05-2019, 06:43 AM
#8
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No codes in vcds. Would I be able to tell if there was a problem with the haldex or diff based off the oil. Both had their fluid replaced just over a week ago and both where long overdue. The diff had no metal in the oil but there was a small amount of shavings on the cap but nothing much and no big pieces and with the condition of the oil it might have been the original oil or at least had not been changed in a very long time. The haldex fluid was also pretty dark and no light would shine through it whatsoever when I put a flashlight to it when it was in a cup but there where no visible particles in it. I let it sit for a couple of days to see if anything would settle out of it but nothing did and I even put a magnet in it for 3 days to see if there was metal in it but there was nothing.
Just like any oil-cooled/lubricated system, you could have issues with the internal pistons and hydraulics of the coupling as a result of oil that was not changed frequently enough. Those plates will naturally break down as a result of wear over time and any tiny particles or grime that builds up will end up circulating through the system. If a PO neglected the Haldex oil changes or the filter change, that can cause issues down the line. BTW - make sure you change that filter out too if you haven't done so. You'll need the special filter wrench for it.
If you have the funds available I'd recommend sourcing a used (working) controller from someplace like car-part.com or similar. Since there are no codes being thrown by the controller, it believes the Haldex is functioning correctly. Replacing it could potentially fix that. You'll also need a new metal gasket to go with it. The job is a PITA in terms of accessibility but isn't very difficult - just time consuming. If a new controller doesn't solve the issue, your next solution is to just replace the entire diff assembly.
03-05-2019, 08:31 AM
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The haldex is still working and engages the rear wheels when it should, should I still try getting another controller and if so do you think that getting one from a pick a part yard would be fine?
03-05-2019, 08:55 AM
#10
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As I said before, I'm really not sure at this point what the exact cause of the noises might be, but swapping in a used controller may solve the noise issue. You can try getting one from a pick yard if you'd like, although I prefer to buy those sorts of parts online from sources that have already tested them to be sure they are working.
If you decide to buy an entire rear drivetrain assembly from a breaker, don't expect that solution to cost any less than $500 or so. A used controller can be had for ~$150 with a little searching, plus the price of the new gasket.