Haldex thump

[emyrmac]

Good Morning people.

I've been looking around for a couple of days for a problem similar to mine but unable to find one. I believe the S1 uses a 60/40 split instead of the usual 100/0 untill the front slips then engages. My issue is if I reverse and then come back to the car a bit later, when I start to set off I get a small thud from the rear diff after a couple of meters as if the haldex is engaging late. The 4wd works when driving 100%. No issues or wierd noises when driving or when lifting off then throttling back on. If I park up without turning the car off...reverse out of a spot for example then set off the noise is not there, only after turning the car off.

The haldex oil was changed about 15/20k back but doubt they checked the mesh filter on the pump so I have reason to believe it may be clogged or something. I will be dropping the oil,.checking the pump and replacing the o rings along with filling with fresh oil this weekend. I have OBDEleven and have seen threads stating you should use the pump reset function after doing this. Has anyone else experienced something similar? I doubt it's a bush or a UJ as it's only there after turning the car off. Many thanks for any suggestions or opinions.

car is on 57k

 

[Phazer]

Yes, the S1 has a different split to other gen5 cars.

There is some slack in the haldex/diff. Mine sounds like clicking brake pads sometimes when I start to reverse. Doesn't thud though and doesn't fit the pattern you're seeing. However, if you believe the gauze has never been cleaned, get that done properly first.

Yes a pump learn is required (though plenty don't), reason being is the work rate of the pump is adjusted as the gauze gets clogged and the oil gets dirty. If you replace the oil and don't do the pump learn then it's working harder than necessary. It's possible it re-learns eventually anyway but no info either way. Biggest one for me is you can fill the oil, do the pump learn and then top up to the required amount. Saves having to go for a drive and then lift it again. Not sure OBD11 can do the learn, I read it only works properly on VCDS, perhaps they've resolved this?

 

[emyrmac]

Thank you for the reply. I took it out yesterday and reversed into a spot then immediately drove out left hand down and it did the subtle thud again. So today I dropped the oil, cleaned the filter which was covered in crap/metal. Filled with fresh oil, reset haldex adaptations and did the pump output test. You could hear the unit run through cycles for just over a minute. Took it for a drive with no noise coming off the driveway then went for a meal and when I left the parking space I reversed into...it didn't thud. Will keep an eye on it but the haldex seemed to test healthy and the live values didn't show anything that would concern me. Next issue....creaking rear doors!

 

[emyrmac]

Just throwing some pictures up for people to see my problem. It was caked in sh*t. OBD11 ran the pump test function just fine incase the next person is wondering

 

[Chris93]

Thank you for the reply. I took it out yesterday and reversed into a spot then immediately drove out left hand down and it did the subtle thud again. So today I dropped the oil, cleaned the filter which was covered in crap/metal. Filled with fresh oil, reset haldex adaptations and did the pump output test. You could hear the unit run through cycles for just over a minute. Took it for a drive with no noise coming off the driveway then went for a meal and when I left the parking space I reversed into...it didn't thud. Will keep an eye on it but the haldex seemed to test healthy and the live values didn't show anything that would concern me. Next issue....creaking rear doors!

Were you able to reset the adaptations using OBD11 out of interest? I need to do this on mine as i have the same issue