Swop out gen2 haldex and diff for gen4 haldex and diff.

[William Theron]

Hi guys i have searched up and down on every forum available but found alot of questions but no real answer. I want to know whether it is possible to swop out my preface 2008 S3's entire diff with gen2 haldex for gen4 haldex with diff from a facelift 2010? Im from South Africa and info is not really as available as well as service and repair centers besides the dealers...i found the low mileage diff complete with gen4 haldex at a very good price but would not want to spend the money and it does not work. Sorry if this is a repeated question but i need the info as a matter of urgency as the diff will not be available much longer.

Thanks in advance.

 

[William Theron]

Anyone have some info here? I would really appreciate the help.

 

[S3Alex]

Anyone have some info here? I would really appreciate the help.

This was an attempted Gen3 to Gen4 swap which failed.

http://www.freel2.com/forum/topic17032.html

Might also be worth dropping an email to HPA Motorsports as they have a lot of aftermarket controller experience.

http://www.hpamotorsports.com/contact.html

My impression of this is it's likely to be difficult at best,and impossible seems likely.

 

[William Theron]

Hi S3Alex,

I spoke to Darryl from HPA yesterday and they cant guarantee that it will work but advised that it is likely to do so. My main issue is that I'm not sure if the Gen4 uses different signals from ECU to operate as I know the unit is different in the way it operates.

 

[S3Alex]

Ahhh...OK,then you've already done the best thing.

That's the problem with trying new things on these cars.....anything like this is a leap in the dark.
Good luck anyhow.

 

[William Theron]

Thanks for the reply, I will speak to the guy selling and hopefully in the name of science he will allow me to test the unit before purchase. I am also in the process of contacting some Haldex repair specialist and hopefully get more info. If anyone has tried this with success you can update as well and I am sure there are more guys out there that would like to get this info.

 

[William Theron]

So I contacted a Haldex specialist and below is their response.


"Although yes you could physically bolt in the Gen 4 Diff to a Gen 2 car, or vice versa.
The problem will come with the Haldex ECU. The Gen 2 and Gen 4 systems require a different ABS, engine ecu and instrument cluster.
Then the Haldex ecu's cannot be swapped between gen 2 and 4 diffs because they fit differently.
Vagcom will not help you.
You are trying to add 2 + 3 and looking for 4.
They are non compatible communications systems. They look for different data/measuring blocks.
So you are stuck to buying the correct one."

So I'm stuck with sourcing a Gen2 setup.

 

[William Theron]

Hi guys just a quick update. My S3 is an October 2008 model and after speaking to a local guy we decided to test the gen4 haldex controller just to see what comes up on VCDS. Well no error codes or faults was found. So I'm going to bite the bullet and install the gen4 complete differential and then go from there. Also a friend of mine has fitted a gen4 controller to his gen2 differential on his S3 2007 and it worked. AWD worked without any errors. So this makes me a little confused as this contradicts almost every post I have read regarding the gen2 vs gen4 haldex units. I will update this as soon as I have the differential fitted, as from my understanding only the ABS control unit links to the controller and if thats the case I will swop out the ABS control unit as well from the donor car.

 

[IPG]

Hi guys just a quick update. My S3 is an October 2008 model and after speaking to a local guy we decided to test the gen4 haldex controller just to see what comes up on VCDS. Well no error codes or faults was found. So I'm going to bite the bullet and install the gen4 complete differential and then go from there. Also a friend of mine has fitted a gen4 controller to his gen2 differential on his S3 2007 and it worked. AWD worked without any errors. So this makes me a little confused as this contradicts almost every post I have read regarding the gen2 vs gen4 haldex units. I will update this as soon as I have the differential fitted, as from my understanding only the ABS control unit links to the controller and if thats the case I will swop out the ABS control unit as well from the donor car.

So what was the outcome here ???

 

[ch1z64]

Me is thinking it didn't work , just as i would hsve thought if he had done it and proved it could be done he would have replied with it being big news

 

[IPG]

Me is thinking it didn't work , just as i would hsve thought if he had done it and proved it could be done he would have replied with it being big news

yes... true

all further readings suggest it doesn't work either

 

[IPG]

Me is thinking it didn't work , just as i would hsve thought if he had done it and proved it could be done he would have replied with it being big news

Looks like the following components are required to make Gen4 to work
- late model ECU
- late model ABS unit
- gen4 haldex/controller

 

[Ttssouthwest]

Hi all,
Thought I'd post my successful experience of replacing my diff (not a retrofit upgrade though).

I got a 2008 TTS, rear diff was whining/Grinding and diagnosed as faulty so replacement was required.

All TTS comes with Gen 4 Haldex as far as I believe.

I sourced a second hand diff off eBay. The part number didn't exactly match but the main numbers was present ie. 525010 - the diff I purchased came off off a 3.2 TT V6.

The garage identified that the diff I supplied, came with a gen 2 haldex. I had them take off my gen 4 haldex off my previous diff and attach it onto the newly supplied one. All works ok with no faults.

Bottom line: provided your car comes with gen 4 as standard, then any diff that matches the main part numbers should work, if you attach the gen 4 haldex systems to it, as it's the same fitment - contradicting every other post.

I'm not sure what's needed if you're trying to retrofit onto a vehicle that's only equipped with gen 2. But as mine is from factory, a gen 4, I wasn't concerned about the ECU compatibility. The main point I'm trying to get at is that most diffs should work if you're replacing a faulty diff, and then just swap over the haldex pump and controller from your previous diff and should work fine as fitment seems to be universal throughout. Garages will say it might not fit but that's only a disclaimer and a risk that you're willing to take to move forward.

Hope this helps anyone.

Thanks

 

[MT-V6]

That's interesting and good to know. Might have to have a look at the parts catalogue and see what the official info is too

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