Hi. First time poster.
Kodiaq rear diff makes a real clunk noise and vehicle ‘jumps’ as if rear diff is suddenly releasing when on tight lock manoeuvring around car park for example. Happens in both forward and reverse after driving about 5-10yards. Removing fuse for haldex pump (obviously gives lots of warning lights on dash) but the noise/issue disappears and car drives fine. I’ve had a haldex service done and lots of debris on the filter and in oil. It was last serviced (and pump replaced due to a different noise in diff) 3 years/30k miles ago. The recent service didn’t solve the current problem so I have had a new pump fitted thinking it might be the pump burnt out but unfortunately this hasn’t solved the issue either.

So at 8-9years old and 145k miles on the clock I’m reluctant to spend a huge amount more on it, not knowing the problem. Does anyone have any experience of this? Or any thoughts on me just removing the prop shaft so rear diff is not driven and drive it in 2wd effectively. I don’t need the 4wd. Alternatively I could just unplug the haldex pump (which doesn’t throw any error messages) but might burn out ecu over time?

any suggestions welcome.

Thanks

Charlie

looking online for second hand differential (not knowing your engine) for a low kilometer one the cheapest is around 1.2-1.3k €

https://ovoko.it/ricerca?man_id=115&cmc=1089&cm=1954&cpc=459&mfi=115,1089,1954;&prs=1&page=1

No direct experience, but being an haldex system normally it drives only the front wheel, so technically, you aren't going to overload the front diff if you unplug the haldex system, in case just isolate the connector from all the atmospheric agent in order to prevent corrosion or water running from the plug to the control unit.

23 minutes ago, Jack25 said:

looking online for second hand differential (not knowing your engine) for a low kilometer one the cheapest is around 1.2-1.3k €

https://ovoko.it/ricerca?man_id=115&cmc=1089&cm=1954&cpc=459&mfi=115,1089,1954;&prs=1&page=1

No direct experience, but being an haldex system normally it drives only the front wheel, so technically, you aren't going to overload the front diff if you unplug the haldex system, in case just isolate the connector from all the atmospheric agent in order to prevent corrosion or water running from the plug to the control unit.

Thanks for your reply. Hadn’t thought of it like that as normally driving front wheels only. So my question then is if I disconnect the haldex system is the ecu going to ‘burn out’ if it’s got no resistance/feedback from the pump?

Is the actual issue the HALDEX or the Rear Diff? Different things? But not unknown for someone servicing the Haldex and draining oil to drain the Rear Diff.

So, logically, if you are moving away slowly without any loss of grip at the front wheels, the coupling should not be providing any gearbox derived drive to load the rear diff - when you remove the Haldex pump fuse you are 100% removing the possibility that any gearbox derived drive is being fed to the rear diff.

Kind of strange situation, are the front wheel tyres the same tread depth as the rear ones - just in case there is drive getting through and "wind up" is happening slightly?

I ran a 1991 VX Cav GSI 2000 16V 4X4 for maybe 8 years back then, I replaced the tyres at one end and in doing so should have removed any difference in tread depth as fitting the same Pirelli model of tyres. It was a bit annoying to after that, find out that when I pressed the brake pedal there was always a "bump" from probably the propshaft support bearing, as we were away from home I just removed the 4WD fuse and that sorted that for the time being. When I returned home I booked the car into my local VX dealership "unequal tread depth between front and rear tyres" was the diagnosis! I measured the tread depth at all 4 tyres and it was exactly the same, so I measured the rolling radius of the front pair and the rear pair, the fronts were the same and the rears were the same, but the fronts and rears had different rolling radius - very annoying. So I gambled on the fronts being the "correct" versions as they came from a "better" local tyre place, and got them to supply another 2 new tyres and fit them on the rear, which were almost brand new, but had a bigger rolling radius. That sorted that out - also, as I retained the almost new but bigger rolling radius tyres from the rear, if I had got the wrong tyres replaced, I could refit the almost new ones onto the front.

I can't explain why that happened, possibly just different factory Pirelli used, these almost new but "bigger rolling radius" for the same tread depth tyres ended up being gifted to the primary school my wife worked for as playground equipment.

Note, with that 1991 VX Cav 4X4, bought slightly used, pressing the brake disengaged the rear drive "to improve stability under braking" - that car was other than that issue, the best car that I have ever owned, only equalled by my slightly used 2011 Audi S4.

Edit:- maybe the Haldex controller is getting duff wheel sensor info from the ABS controller at slow speeds - or a wiring issue.

Second Edit:- I'm assuming that when the Haldex was service, "re-learn" procedure was run to optimise the Haldex clutch gripping, same for the next pump? Mind you, the pump should only be running and so applying pressure to its clutch pack when front end slip is being detected - still sounds a lot like inconsistent/incorrect being fed to the Haldex controller front the ABS system.

Edited 13 March13 Mar by rum4mo