Diff/haldex sump plug stripped threads....

[RaceDiagnostics]

What a pita, I changed the rear diff oil, then the front diff oil, then on to the haldex clutch oil. Drained, refilled and when I was tightening the sump plug, it gave way. From the pic it looks like a chunk of thread broke off, or was never there. Bottom two threads stripped out.

Unfortunately there is no sump pan just the complete unit. £10k for a new one, £1k on eBay.

Anyway, I've ordered up a set of M20 taps that will be here tomorrow and take it from M18 up to M20 as there is still plenty of meat round the opening.

 

[roofman]

plenty of Ptfe tape and it will hold...get some brake/clutch cleaner on threads 1st to enable the tape to mesh in without sliding.

 

[Dozzer]

Had this on few VW sumps, found the thread inserts work well.
there are kits just for fill bungs. and seem to last longer than the parent metal!!

 

[RaceDiagnostics]

So why did it happen, I think it was because I used a new aluminium washer where there was none when I removed the plug. The procedure said replace the washer, but odd that there was none in the first place. Anyway I think that adding the washer meant that there were only a couple of threads engaged when I torqued it up. Obviously too few.

 

[Dozzer]

So why did it happen, I think it was because I used a new aluminium washer where there was none when I removed the plug. The procedure said replace the washer, but odd that there was none in the first place. Anyway I think that adding the washer meant that there were only a couple of threads engaged when I torqued it up. Obviously too few.

You did a neat job of removing the threads

 

[Ubique]

Experienced similar on VWG engine sumps, there are two sizes of sump plug, the one with a longer thread is for Alu. sumps, the shorter for steel. I'm sure you can guess how & why the threads are stripped....
Anyway, the incomplete threads further in will hold a sump plug OK, there are plenty of longer plugs available if you look beyond that particular application - I think Haldex is M20 x 1.5 but you'd obviously need to check, if it is, then ZF 6HP26 transmission fill plug is that size but longer.
edit - just seen it's M18 in your later post! personally I'd be tempted to use the undamaged threads rather than risk introducing swarf to the insides....

 

[RaceDiagnostics]

Experienced similar on VWG engine sumps, there are two sizes of sump plug, the one with a longer thread is for Alu. sumps, the shorter for steel. I'm sure you can guess how & why the threads are stripped....
Anyway, the incomplete threads further in will hold a sump plug OK, there are plenty of longer plugs available if you look beyond that particular application - I think Haldex is M20 x 1.5 but you'd obviously need to check, if it is, then ZF 6HP26 transmission fill plug is that size but longer.

It's M18, I'll have a look for a longer one and also give that a try.

 

[nickk]

Exactly what is HALDEX .

 

[RaceDiagnostics]

I was initially confused about the section of missing thread but I now think that is to aid with draining the fluid.

 

[RaceDiagnostics]

Exactly what is HALDEX .

It's an electronically controlled clutch that feeds power to the front wheel in this case.

 

[Dozzer]

It's an electronically controlled clutch that feeds flower to the front wheel in this case.

 

[Dozzer]

Exactly what is HALDEX .

A PITA that VAG cars used to replace things like viscous couplings and torsen diffs in 4 wheel drive systems.

 

[Ubique]

IIRC a Boxter 996 uses M18 sump plugs

 

[nickk]

A PITA that VAG cars used to replace things like viscous couplings and torsen diffs

So ,there designers philosophy;if it ain’t broke,let’s design something that’s complicated and will break. Glad my love of VW ended in the early 2000’s.

 

[Ubique]

A PITA that VAG cars used to replace things like viscous couplings and torsen diffs

And Volvo, JLR etc. etc. if maintained, they're usually reliable, the biggest issues are the control module mounted on the casing corroding & failing and the differential input shaft seal failing, allowing the Haldex oil & the differential oil to mix.

The advantage they have over purely mechanical systems is they can be locked up predicatively (and proportionally) to maintain traction, rather than try to regain it - and of course, give better fuel efficiency than a mechanical system.

 

[RaceDiagnostics]

IIRC a Boxter 996 uses M18 sump plugs

This one is on a 997 so the same.

 

[roofman]

Does not help by thread being cut into a casting, some monkey in the past has swung off a ratchet with it having no crush washer to get a seal from the nut face

 

[Ubique]

This one is on a 997 so the same.

Should be the same as your engine sump plug then!

 

[Dozzer]

And Volvo, JLR etc. etc. if maintained, they're usually reliable, the biggest issues are the control module mounted on the casing corroding & failing and the differential input shaft seal failing, allowing the Haldex oil & the differential oil to mix.

Just give me a tosren diff any time, they work, are not prone to locking up, not working, and a whole host of issues that moisture and electronics cause, had to replace control module on the Haldex on the 4 motion van few years ago thanks to connector corroding so badly.
Never had that problem with my Syncro, or the old audi Quarto system.
Just had to change the transfer case in my D3 as the motor/clutch refused to calibrate and it was leaking.
Enshitification

 

[bricol]

Just give me a tosren diff any time, they work, are not prone to locking up, not working, and a whole host of issues that moisture and electronics cause, had to replace control module on the Haldex on the 4 motion van few years ago thanks to connector corroding so badly.
Never had that problem with my Syncro, or the old audi Quarto system.
Just had to change the transfer case in my D3 as the motor/clutch refused to calibrate and it was leaking.
Enshitification

The torsen in the rear of my integrale is still going strong after 35 yrs and 209,500. Front diff and Ferguson centre diff seem to be holding up well too.

The Japanese bearing in the German "transfer" box bolted to a Italian box attached to Australian V6 in my Alfa 159 however - failed at 90,000 ish. Crap design with how the collapsible spacer to provide bearing pre-load rode up the shoulder it bore against, losing the pre-load and wrecking the output bearing. "Non-serviceable" according to ZF. Ignored that and fixed it