Viking Posted February 26, 2019 Report Share Posted February 26, 2019 Been having ongoing issues with my new Yeti being 2 wheel drive rather than 4 wheel drive. Decided it was time to have a look see why. Gen 5 Haldex doesn't have a filter (according to Skoda) so their service regime for the Haldex unit is simply drain the oil and refil. Also, the Haldex pump is dumb (doesn't report to VCDS on a scan) so no fault codes will be present. Any issue with no rear wheel drive is simply put down as "Haldex checked and serviced, no fault found" because they're too dim to actually check if it physically works. So, I set too last week with a set of ramps and tools, and dropped the pump off to check the gauze filter on the pump. This is what I found... This was after I'd wiped it somewhat in holding it to remove from the pump body, but essentially it was fully clogged and had blocked the pump. What happens then is the pump is starved of oil and siezes as a result, meaning no drive to the rear wheels. So, on a vehicle with two Haldex services (one last year at 1000 miles previous to current mileage) the pump was shot due to clogging of the filter which doesn't exist. It's currently booked into the local VW specialist for diagnosis and warranty repair. Curiously the first place I was instructed to take it to asked "What's a Haldex?" when I called to book it in and give them the details of the problem, which didn't give me much confidence really. I was also told that I would be responsible for the diagnostics charge which I should claim back from the warranty company once I'd had the repair done. I went back through the warranty and asked for a different repair shop, and when I told the new place what the problem was the guy said "I'm not a betting man but I suspect it's the Haldex pump which has failed." So, this weekend I'll be under the Tiguan and removing the pump from that to clean the filter which doesn't exist. Quote Link to comment Share on other sites More sharing options...
Geoffers Posted February 26, 2019 Report Share Posted February 26, 2019 Classic case of fitters not engineers. One one hand you must be pleased you've found it, on the other very annoyed the "professionals" let it get in such a state. Mind you, as it doesn't exist it doesn't have to be cleaned.... Quote Link to comment Share on other sites More sharing options...
Viking Posted February 26, 2019 Author Report Share Posted February 26, 2019 If I were the only one then it would be understandable, but it's fairly widespread, with mileages as low as 20k. Quote Link to comment Share on other sites More sharing options...
Tony Posted February 26, 2019 Report Share Posted February 26, 2019 Dumb question.... Is it a fuel or oil filter?.... Quote Link to comment Share on other sites More sharing options...
Viking Posted February 26, 2019 Author Report Share Posted February 26, 2019 It's a hydraulic pump Tony. The Haldex unit on a 4x4 is essentially an automated centre diff. It allows for no drive to be transmitted to the rear axle until the front wheels start to spin, then hydraulic pressure is used to operate a clutch which switches the rear drive in. So the pump runs all the time to keep pressure in the hydraulics so that it switched in immediately, and the filter is on the pump inlet. Quote Link to comment Share on other sites More sharing options...
Tony Posted February 26, 2019 Report Share Posted February 26, 2019 Do you think the fluid degraded the rubber in the system. Quote Link to comment Share on other sites More sharing options...
Viking Posted February 26, 2019 Author Report Share Posted February 26, 2019 I don't think it's rubber degrading. I guess it's just the usual contamination from parts wearing due to friction . Quote Link to comment Share on other sites More sharing options...
Rich Posted February 26, 2019 Report Share Posted February 26, 2019 Wow that was clogged up!! Well done for finding the problem. What warranty are you using, a dealership one or is it one of those 3rd party ones? Quote Link to comment Share on other sites More sharing options...
Viking Posted February 26, 2019 Author Report Share Posted February 26, 2019 It's a dealer supplied aftermarket warranty, branded as AA Warranty, administered by Motorway through Prestige or something like that. The ggod part seems to be that everything is included. Usually you get charged for fluids and other consumables. Quote Link to comment Share on other sites More sharing options...
fluff34567 Posted November 16, 2019 Report Share Posted November 16, 2019 It's quite a common issue on vw so same family group. Quote Link to comment Share on other sites More sharing options...
NickT Posted November 16, 2019 Report Share Posted November 16, 2019 These links might be useful: https://www.haldexrepairs.co.uk/generation-5-haldex-fault-finding-repair-guide/ https://www.haldexrepairs.co.uk/guide-generation-4-haldex-trouble-shooting/ My interpretation is: The Gen 4 has a separate filter cartridge, like a fuel filter. The pump has a coarse filter gauze on the pump. The Gen 5 does not have a separate filter, but still has the filter gauze on the pump. I think this is why the dealer stays that there is no filter. However, the gauze on the pphone IS a filter! After an oil change in the haldex they are supposed to remove the pump, clean the gauze then do a relearn on the ecu etc etc. It looks like s the engineer you are, you've done the right thing in cleaning this out by removing the pump for inspection, rather than a garage mechanic following a guide on what to do on a service. You might want to look to see about getting the pump learn sequence done by the vag software. Great post as I'll monitor the 4x4 system on my soda superb, and I'll watch this post on your results too. Quote Link to comment Share on other sites More sharing options...
Viking Posted November 16, 2019 Author Report Share Posted November 16, 2019 VCDS can do the pump relearn. As regards haldexrepairs, I was talking to him at length about my problem, in fact some of the pictures he's using on his guide are ones I screen shot while I was fault finding for him. He's a good lad. Quote Link to comment Share on other sites More sharing options...
NickT Posted November 16, 2019 Report Share Posted November 16, 2019 Excellent work there. Let's hope you get yours sorted quickly, if it's not done already. Quote Link to comment Share on other sites More sharing options...
Viking Posted November 16, 2019 Author Report Share Posted November 16, 2019 This is an old post been resurrected by someone... Quote Link to comment Share on other sites More sharing options...
NickT Posted November 16, 2019 Report Share Posted November 16, 2019 Doh Quote Link to comment Share on other sites More sharing options...
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