Hi everyone - apologies for invading your forum, I don't have a Land Rover, though a good friend of mine is the local LR/RR guru. He services a couple of Freelander 2's, but hasn't done the Haldex service on any, so I haven't been able to look inside one.

I'm working on using a Haldex "inline" in the propshaft of a different AWD car, replacing a viscous coupling. I've bought a Gen 4 Haldex (from a Volvo) and I'm designing a housing, output shaft and new electronics for it, but I don't know the dimensions of the cavity in the diff housing, or how much "sump" there is. The haldex unit was posted to me, the diff housing it was removed from is a long way away.

I've shamelessly stolen this picture from another thread, showing the part I'm interested in - the photo was taken looking towards the left side of the housing, but I'm pretty sure there is a cavity on the right side which acts as the sump for the haldex oil. There's a square o-ring seal at the front, so a relief for that, but I don't know much else.



Can anyone help me out?

thanks
Simon

Does this help? Let me know if you need specific dimensions.

 (Now Sold). 2008 Freelander 2 (Nazca Sand) SE TD4 Auto. Statutory write off & on WOVR for hail damage but still road legal.
171037Km as of 09/05/22
Superchips Bluefin Flash
Nanocom Evo II (also sold)

That's fantastic, and helps me a LOT!!

It now makes sense what the pump inlet hole aligns with - the outlet from that sump.



From the photo, it appears there is a hole in the back of the housing, below the diff input shaft, do you think that is a gallery for oil to return/equalise to the sump? otherwise the only way for oil to get in there is from the squirters on the back of the clutch pack to throw it up to the top of the housing or bleed back through the pump when stopped, is there any other way you can see for oil to get in there while driving?

Any dimensions you could give me would be great - these are what I'd really like - I've annotated your picture (attached)

The width of the machined section of the bore (seems like it's ~122mm) - red line
The width of the raw cast section of the bore - green line
The depth of the bore from the front of the mounting flange back to the machined face - blue line
The length and width of the diff input shaft nose - it sits in a needle roller bearing inside the clutch pack so is a critical dimension

Those three oil galleries are all interconnected, I believe. The large upper one is where the filler plug is located for the Haldex.

As far as your blue line goes, it is probably not clear from my pic, but there are probably two or three different depth machined faces!

I've given you the outer diameter one, but I suspect (thinking about it now), that it will be the face that the thrust bearing sits against that you really need. I can get that tomorrow.


The width of the machined section of the bore (seems like it's ~122mm) - red line = 122mm
The width of the raw cast section of the bore - green line = 125.4mm
The depth of the bore from the front of the mounting flange back to the machined face - blue line =81.5mm
The length and width of the diff input shaft nose - it sits in a needle roller bearing inside the clutch pack so is a critical dimension = 15mm L x 16mm Dia. (Now Sold). 2008 Freelander 2 (Nazca Sand) SE TD4 Auto. Statutory write off & on WOVR for hail damage but still road legal.
171037Km as of 09/05/22
Superchips Bluefin Flash
Nanocom Evo II (also sold)

that's brilliant, thanks Badger, I really appreciate it

81.5mm at the side of the cavity would make sense, the outer part of the basket is about 81mm when there is no clutch pressure to pull it in, the torrington bearing is another 5mm on top of that, so I'd expect you to find that face will be around 87mm, give or take. I guess the seal is a bit deeper again

Are there any witness marks on that face that look like the bearing has been touching it?

The picture I posted yesterday of the torrington I think shows it hasn't been in contact with the housing. When the clutch pack is pressurised, the basket pulls in towards the front of the car, when it releases, the basket pushes back. Logically, when it pushes back it's turning at wheel speed * diff ratio, so quite fast. If it touches the stationary housing, I reckon there should be marks on it..

The drillings in the diff case, which forms part of the Haldex sump, are placed and angled to ensure the fluid goes where it's needed.

The drilling closest to the diff is placed inside the clutch pack thrust bearing, being angled to draw fluid into the centre of the clutch pack under forward rotation of the clutch basket. The clutch basket also has scooped drillings, which are designed to push the fluid through the clutch pack.

The large upper casing drilling is there to collect fluid that is spun outwards from the spinning basket, ensuring a constant supply of fluid to both the pump inlet and the previously described clutch pack supply drilling.
The fluid level in the Haldex isn't filled to the top, the level being sufficient for fluid to enter the large upper drilling when the basket is stationery, so there's always fluid available for the pump to function.

Could you use an old or damaged diff by cutting off the front section, rather than making something custom?

In my experience, a VCU is more reliable than a Haldex, so are you sure it's actually worth the effort? 2009 Rimini Red SE TD4. Soon to be sold.
Hyundai Ionic 5 Ultimate on order.
Gone. 2006 Tonga Green i6 HSE.

Nodge68 wrote:

The drillings in the diff case, which forms part of the Haldex sump, are placed and angled to ensure the fluid goes where it's needed.

The drilling closest to the diff is placed inside the clutch pack thrust bearing, being angled to draw fluid into the centre of the clutch pack under forward rotation of the clutch basket. The clutch basket also has scooped drillings, which are designed to push the fluid through the clutch pack.

The large upper casing drilling is there to collect fluid that is spun outwards from the spinning basket, ensuring a constant supply of fluid to both the pump inlet and the previously described clutch pack supply drilling.
The fluid level in the Haldex isn't filled to the top, the level being sufficient for fluid to enter the large upper drilling when the basket is stationery, so there's always fluid available for the pump to function.

Nodge68 wrote:

Could you use an old or damaged diff by cutting off the front section, rather than making something custom?

Nodge68 wrote:

In my experience, a VCU is more reliable than a Haldex, so are you sure it's actually worth the effort?

simon k wrote:

that's brilliant, thanks Badger, I really appreciate it

81.5mm at the side of the cavity would make sense, the outer part of the basket is about 81mm when there is no clutch pressure to pull it in, the torrington bearing is another 5mm on top of that, so I'd expect you to find that face will be around 87mm, give or take. I guess the seal is a bit deeper again

Are there any witness marks on that face that look like the bearing has been touching it?

The picture I posted yesterday of the torrington I think shows it hasn't been in contact with the housing. When the clutch pack is pressurised, the basket pulls in towards the front of the car, when it releases, the basket pushes back. Logically, when it pushes back it's turning at wheel speed * diff ratio, so quite fast. If it touches the stationary housing, I reckon there should be marks on it..

simon k wrote:

Nodge68 wrote:

The drillings in the diff case, which forms part of the Haldex sump, are placed and angled to ensure the fluid goes where it's needed.

The drilling closest to the diff is placed inside the clutch pack thrust bearing, being angled to draw fluid into the centre of the clutch pack under forward rotation of the clutch basket. The clutch basket also has scooped drillings, which are designed to push the fluid through the clutch pack.

The large upper casing drilling is there to collect fluid that is spun outwards from the spinning basket, ensuring a constant supply of fluid to both the pump inlet and the previously described clutch pack supply drilling.
The fluid level in the Haldex isn't filled to the top, the level being sufficient for fluid to enter the large upper drilling when the basket is stationery, so there's always fluid available for the pump to function.

Thanks for that Nodge - a very useful explanation - you're right now that I look at it again, those pressings in the face of the basket aren't squirters at all, they're going the wrong direction, they're scoops like you say. The location of that drilling underneath the output bearing seems a bit odd when first looking at it, but it makes sense that it'd be a feed into the basket

Nodge68 wrote:

Could you use an old or damaged diff by cutting off the front section, rather than making something custom?

That's definitely a smart option - The FR2 diff housing and the large bracket/hanger underneath does package it really well, slicing the front off it would work. When looking for a Haldex, I contacted some wrecking yards about buying a whole FR2 diff, but they must think they're made from solid gold.. I hadn't discovered this forum before I bought the Volvo unit - I'll put up a "wanted" ad

Nodge68 wrote:

In my experience, a VCU is more reliable than a Haldex, so are you sure it's actually worth the effort?

There are a lot of silly things we do on with old cars that aren't worth the effort - but for some reason we keep doing them.. I have no idea why.

In my case, I'm building a car for competition - I do everything from motorkhanas to circuit sprints - for motorkhana in particular I need to be able to do a handbrake turn, a VCU doesn't allow it - with a Haldex I can drop the rear drive as soon as I touch the handbrake, reengaging when I let it go, but also vary the lockup on demand, put a knob on the dashboard, different settings for different surfaces, fully sick 4wd drift mode, varying based on steering angle input, brake force, I can even imagine how I'd integrate some AI... what could possibly go wrong??

If I had half a brain I'd go and buy an early Audi TT Quattro to race, but that wouldn't cause me nearly enough angst, frustration, expense...

Badger51 wrote:

Simon, I make the measurement 84.2mm & there are definitely witness marks on that face. The seal is 10mm deeper again.

I do have a diff for sale on gumtree, which you would be welcome to, but I think the freight cost might kill it, might be worth checking out though.

Nodge68 wrote:

It's a shame you're on the other side of the planet, as I've got a busted FL2 diff waiting for disposal.

You could have my diff for a lot less than the asking price on gumtree, most of that is to cover the cost for the bearings/seals etc. It might be worth your while getting a quote from somewhere like truckit, to see what you can get it delivered for. (Now Sold). 2008 Freelander 2 (Nazca Sand) SE TD4 Auto. Statutory write off & on WOVR for hail damage but still road legal.
171037Km as of 09/05/22
Superchips Bluefin Flash
Nanocom Evo II (also sold)

simon k wrote:

how busted?

good news!

Yesterday I found a wrecker on gumtree selling a complete VW Tiguan diff with Gen 4 Haldex ($125, with 12 months warranty! )

It arrived at work today ($160 freight )

 (Now Sold). 2008 Freelander 2 (Nazca Sand) SE TD4 Auto. Statutory write off & on WOVR for hail damage but still road legal.
171037Km as of 09/05/22
Superchips Bluefin Flash
Nanocom Evo II (also sold)