# Haldex Question



## wrestler4life521 (Aug 12, 2010)

Believe me, I have done my searching, there were a lot of haldex threads but none that matched my symptoms. 

So here is the deal. When the car has all 4 wheels jacked up, in 1st gear and in idle they all spin. (However I can put my foot on one of the rear wheels and with enough pressure only 3 wheels will spin) Don't know if this is normal. 

I have also done the circle test with the 3000 rpm to determine whether the haldex was working, and it seemed like it was. 

So here is the issue. I know that our cars are FWD favorable, but i am losing traction in the most ridiculous situations. On brick roads, barely wet roads, slightly sandy roads. Is this normal? I am not pushing it when I lose said traction. I don't know, but to me personally I feel like the haldex system should be more functional than this. So what I am asking is if this is normal or my symptoms sound like I am having a problem. Any and all advice is very appreciated.


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## Marcus_Aurelius (Mar 1, 2012)

Tires on the car, wheel/tire combo, suspension condition? 

Tire conditions, alignment, suspension components play a big role in traction (maybe more than AWD and haldex itself). I ran bad tires in my EVO once and a friend told me, after fighting my car in the streets, that I have the best track handling car he's ever driven but at the same time the worst street handling car he's ever been in. The difference was tires, on slick surfaces and rain, you'd better be prepared as the front would wash out, and the back would come around to bite you if you lifted (kind of liked it as it kept my driving sharp ).

So, if your circle test proved that Haldex is functioning and you have no codes, most likely it's something else. All fingers are pointing at tires and suspension!


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## wrestler4life521 (Aug 12, 2010)

Thanks for the response Max. 

I guess I have pretty crappy tires (nankang 2's... It was an emergency this summer and I had to go cheap to make it back to school)

As for suspension I have ST coilovers. These did put my alignment out of whack so I installed adjustable control arms in the rear and my alignment came out perfect. 

I guess it is easy to lose sight of how important tires are, looks like I will be investing in a better set when the time arrives (hoping these are the culprit. Thanks again. :beer:


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## crazybohunk (May 24, 2011)

*Haldex question*

Hi there,

Max is so knowledgeable it makes my head hurt reading his threads.

However I might be able to shed some light on this issue.

I have a Quattro TT 225 & this sounds similar to my experience.

So on dry pavement even with crap bald tires the Quattro Haldex should kick in pretty quick and there should be little to no wheel spin.

On mine I was breaking loose on dry pavement and it was stupid on wet surfaces.

It turned out to be the precharge pump or Cargo pump on the haldex unit.

It failed and when it does no Haldex no Quattro just front wheel drive and plenty of wheel spin

The way it works is it pressurizes the Hadex Fluid in the haldex clutch pack so they engage when the controller requests it.

When the car is towed and not running it is front wheel drive only can can be towed safety because the pump is off and the clutch pack is totally disengaged.


Now you can test this by hooking up the Rosstech Vagcom diagnostics it has a test mode that will manually pressurize the pump and you can hear it clearly when it engages.

no noise=no pump no pump=no Quattro.

It costs about $500 to buy from on line Audi parts places or you can retrofit the guts of Volvos version of it to save a couple hundred bucks.

It can be a do it yourself project but is a bit of a PITA to get to.

So Vagcom will help if you can get your hands on one or have someone that has the sofware/cable.

Good Luck 

Randy.


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## Marcus_Aurelius (Mar 1, 2012)

Very good post Randy! :thumbup:

I based my reply on the fact that there was mention of a haldex test that confirmed haldex operation. It definitely wouldn't hurt to do the pump test to double check. With haldex completely off, like your case, it would be an unmistakable behavior (at least it was in my car with relentless longitudinal front wheel spin but not necessarily lateral traction loss). In any case, a follow up would be nice for future references. :beer:


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## wrestler4life521 (Aug 12, 2010)

Hey guys, as requested updating this after having had the car vag commed. In test mode, I could definitely hear the haldex pump working. I'm assuming the only other possibility is slipping clutch packs? This would explain all 4 tires spinning when lifted off the ground, but little to no feedback in the rear when getting on it.


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## crazybohunk (May 24, 2011)

wrestler4life521 said:


> Hey guys, as requested updating this after having had the car vag commed. In test mode, I could definitely hear the haldex pump working. I'm assuming the only other possibility is slipping clutch packs? This would explain all 4 tires spinning when lifted off the ground, but little to no feedback in the rear when getting on it.


Hi there,

I have spent quite a bit of time delving into the inner workings of the TT Haldex system.

I even bought a complete used rear differential so I could do an automotive autopsy 

If it was the haldex controller acting up then VagCom should have thrown a code out on it.

I have heard of one case where the ground wire on it was corroded/busted and disabled the controller but again Vag com diagnostics should have thrown a code on it.

The clutch pack could be slipping but from my going to through all of the TT sites and going through all of the threads on this I could only find one case where the clutch packs failed and it was a stupidity issue involving a two wheel dyno test where they did not disable the Haldex for the test and fried the clutch pack.

If the clutch pack is in fact failing then you have to buy the complete rear differential assembly including the clutch pack.

This will cost you normally a grand used unless you get really lucky or 3k new

Before you go to that extreme remove the pre-charge pump and replace it.

The problem with the pump is the haldex fluid seeps into the electric motor assembly 

So the motor may be spinning but not with enough force to pressurize the system due to the guck in there.

On my TT the pump was totally dead and full of gunk.

On the differential I bought for test purposes the pump worked but barely when I put power to it it would spin but not very strongly or it would spin and then stop until I knocked it with a screw driver.

On disassembly of that one it was full of Haldex fluid gunk.

On a brand new pump that I bought when I put power to it on my work bench it would spin a lot faster and with a lot more torque.

I hope this helps.

Randy.


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## Chuckmeister87 (Nov 10, 2009)

http://www.ebay.com/itm/2004-Volksw...Parts_Accessories&hash=item20c4b3a656&vxp=mtr


Used, 72k miles on it from an R32, only $599 + $60 shipping


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## MEDEL514 (Jan 12, 2002)

Great Haldex info on this thread! I'm currently troubleshooting a FWD only issue with my Quattro and I'm at a loss. VAGCOM check'd good, no rear wheel spin on a lift, and failed circle drive test. I have no AWD whatsoever. I need to get this figured out before the snow starts to fall!!

How-do-you-test-a-Haldex-AWD-to-see-if-the-rear-wheels-are-getting-traction


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