N/S Front diff leak

[Nobby]

Noticed a slightly acrid smell coming from the car yesterday and turns out its diff oil leaking from the N/S.

Had a quick look in my workshop manual and it doesn't really cover what is needed to fix the leak. I've changed the CV boots god knows how many times, but how do you get the inner flange off? There is a cover plate which looks like it has 3 or 4 bolts holding it on. Do I need a puller or is there a centre bolt holding it on too?

Also heard mention somewhere else that there isn't a drain plug for it. Assume there is a filler though and fill up until it comes out.

Cheers
Chris

[Mark-RS]

HAHA ! You said Flange !

Sorry I can't help with anything else

[Shoppinit]

There’s one side that you can change the seal on in situ and the other which needs the box to come out, if I remember correctly. Been a while since I’ve looked at it. I’ll have another look to see if it sparks any recollection.

[Nobby]

Found a vid on YouTube for the ZF5HP24 (although it says 5HP24A in the description) gearbox and it looks like the flanges just unbolt. One side (think its my side) comes out with a shaft attached). The gearbox was removed from the car though.....

[Nobby]

Shop I remember someone having a bad amount of axial play in one side of there diffs and the gearbox needed removing to fix. Hoping if its just the seal that not needed..... crossing fingers and toes....

[Nobby]

Found a couple of threads

Leaking and play in the diff (mine doesn't seem to have any play though) - viewtopic.php?f=2&t=106527&p=632180&hil ... ay#p632180

Mav was the one who had diff problems - his is the other side to mine though. viewtopic.php?f=2&t=103961

[Nobby]

Looks like i’ve found a mini guide to what’s needed (think from someone who has a phaeton).

https://forums.vwvortex.com/showthread. ... eplacement

I’ll do a bit of digging for part numbers and get it changed next week. I’ll stick some photos up when i’m done. Looks like i’ll need to get my hydraulic press out!

Chris

[Nobby]

Minor update: Ordered all the bits last week from my local TPS. Went to collect on monday and some parts are on back order..... - including the main seal which I need. I'm gonna replace all the parts along that shaft (excluding the shaft itself), new hub bolt and some subframe bolts if I need to lower the subframe a little.

Guess I'll have to look at topping it up and do it properly next week. I found a few more videos of people taking apart the gearboxes in stages, but some are in French.

One thing I need to confirm - the front diff fill is on the the O/S (there's no drain plugs) and that is for BOTH sides of the differential. It looks like the shaft goes through a long tube which links it to the other side and that separates the gearbox oil from the differential oil. Can anyone confirm this please?

[Shoppinit]

Yup, there is only one fill hole for the front diff. I would expect the assembly to communicate since it's just a boggo diff.

Good luck with the job. If you can take some photos while you're doing it that could be helpful.

[Shoppinit]

It doesn't look like a fun job, but at least you might be able to get away with not dropping the subframe.

Make sure that you drain the diff oil before starting. It looks like if you pull the shaft out when it's full then it allows diff oil to spill into the ATF.

[Nobby]

All the bits have arrived! But I don't have time to change them now so it'll have to wait till next week.

Over £150!

[Nobby]

It doesn't look like a fun job, but at least you might be able to get away with not dropping the subframe.

Make sure that you drain the diff oil before starting. It looks like if you pull the shaft out when it's full then it allows diff oil to spill into the ATF.

Are you sure Shopp? The O/S flange/shaft goes through a long tube which is pinned in place (and can't be removed unless you remove the gearbox as its staked from the bell housing side). I'm gonna drain it out anyway as I've never changed it. Assume as there's no drain its a vac pipe/syringe into the refill hole.

[Shoppinit]

Yeah, it says explicitly in the workshop manual that you'll get cross-contamination if you don't drain.

It's hard to tell looking at the exploded diagrams, but I don't see where the tube is fixed. There's a snap ring on the drive shaft side that suggests it's fixed at the outer end, rather than the inner end. Or maybe when you remove the bearing housing the o-ring doesn't make a good seal any more and allows oil to flow into the box.

It'll no doubt become obvious when you start pulling it apart, but I would err on the side of caution.

It's moot anyway if you intend to replace the diff oil. Yeah, you'll need to syringe it out. I don't think there's much in there. Maybe a litre max.

[Nobby]

Well, the good news is its done!

I'll be writing up a how to shortly. In the meantime, I'll let you all guess how long it took me and leave you with an amusing story:

Draining oil isn't my favourite thing, especially when its gear oil which practically makes me gag. Even following the strictest procedures some oil always gets on the floor, so I mopped up what I could and lighly dusted the remaining patch with some cement dust. X hours later and all finished, I was in the shower getting rid of the stank and something odd has happened to my hair. I normally have styled wax in my hair. The excruciating bank holiday heat meant my head was pretty sweaty too, and ofcourse I'd been lying on the floor (with some protective mats though I might add). My head must have touched the cement though, and the mixture had dried into nice dreadlock clumps It took a lot of washing to get it out!

I thought I might need to get the razor out