I changed the diff oil last year soon after I got the car and apart from being a bit dark it was OK. When I was checking the level last week the bit that dribbled out looked creamy. I drained it (700ml) and it looked horrible. I replaced it, then drained again after 15 miles or so - still creamy but not as bad. There is a slight weep from the RH driveshaft seal, but was only enough to dampen the casing - not drip on the drive. I guess if oil can leak out, moisture can get in but surely not very much. The breather hose is attached and looks intact as far as I can see without removing it.

I'm going to get some more 80W90 and change it again but has anyone got any ideas what could be causing the contamination and what I can do to sort it? How much water would it take to make the oil emulsify? And is it a huge problem anyway?

Thanks



[img]https://www.freel2.com/gallery/albums/userpics/27036/normal_20220617_100704%5B3
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OK it's a while since I had a FL2 but water in the differential was never a problem, and I regularly took her wading deeper than the allowed limit.

Draining the oil just after a run will usually get some frothing, but that looks a lot - could the oil not be the right specification? It's not just plain 80-90W.


Recommended by LR: CASTROL EPX 80-W90 rear differential lubricant (All synthetic API 5 APPROVAL): cod. LR003156

Specification stolen from a post by John Capri in 2019 Tangiers Orange - gone, missing her
Replaced by Ewok what a mistake - now a happy Disco Sport owner

Andy thanks. Last time I used Ravenol epx 80w90 gl5 which, according to their website, was suitable. Castrol epx is listed as mineral rather than synthetic as was the ravenol. (I don't know enough to say what the difference between mineral and synthetic matters). Maybe it reacted with whatever was in there previously? But I'll flush it again and see what happens. My worry is I have a 300+ mile run next weekend and don't want to destroy it

The Diff has a breather

If it is broken or disconnected and you drive thru some water you can get water inside the diff.

Take the brown liquid and put it in a clear plastic container (empty water bottle or similar) mark the top of the fluid with a Sharpie or similar.

Let the fluid sit

One of three things will happen

1. The level will drop significantly (you had air in your fluid and it made its way out)

2. The level is the same but now you have water on the bottom and Oil on the top

3. The fluid stays brown with no change (it is contaminated with something other than air or water, possibly Haldex fluid, if the seal between the diff and Haldex fails)

Let us know

Thanks

Paul

AndyMc wrote:

Andy thanks. Last time I used Ravenol epx 80w90 gl5 which, according to their website, was suitable. Castrol epx is listed as mineral rather than synthetic as was the ravenol. (I don't know enough to say what the difference between mineral and synthetic matters). Maybe it reacted with whatever was in there previously? But I'll flush it again and see what happens. My worry is I have a 300+ mile run next weekend and don't want to destroy it

I keep following this breather thread as I think that is a problem we have. We was towing the caravan and had lots of oil up the front of caravan. Could not see where it had come from and reading on here we’re waiting for mechanic to have it to look at.

Paul, Thanks. I've got some more fluid on order, when it turns up I'll change the fluid again and do as you suggest.
I had a look at the Haldex fluid and its darker than when I put it in last year, but it does not seem to be contaminated so I'm guessing the seal between the two is probably OK. Tomorrow Ill check the full length of the breather - its definitely attached at the diff end.

Jules, this time I've ordered "cheaper" Comma fluid of the correct spec as I do not want to use the good stuff just to flush out the diff. If I can get it clear I will then refill with something else.

Andy

The seal between the diff and Haldex is a labyrinth seal, so if its installed in the correct place, oil or Haldex fluid would drip out the weep hole in the bottom of the casing, which is positioned adjacent to the seal's labyrinth.

If the diff seal isn't in the correct position and blocking the weep hole, then it is possible for Haldex fluid to enter the diff, which would raise the fluid level above the plug bottom, so would spill out when the fill/level plug is removed.
It also colours the diff oil black, not white, so I would guess it's got water in the diff somehow.

LR say you need some special oil in the diff, but it's just a standard diff, so any oil of the correct grade will be fine, especially if you're likely to be changing more often than LR specified. I use 75w 90 in mine, it's fine. Hyundai Ioniq 5 Ultimate. The family car.
2009 Rimini Red SE TD4. Gone.
2006 Tonga Green i6 HSE. Gone.
Audi A5 convertible, my daily driver.
1972 Hillman Avenger GT, the project.

Our mechanic thinks the reason that the oil came out is may be the bearing in the diff got hot, expanded the oil and causing it to blow out. Is it looking like the diff is on the way out ?

My old diff got very hot before it seized up. However my diff was a replacement, and was empty, not a bit low, but completely empty.
Needless to say, the diff was scrap. Hyundai Ioniq 5 Ultimate. The family car.
2009 Rimini Red SE TD4. Gone.
2006 Tonga Green i6 HSE. Gone.
Audi A5 convertible, my daily driver.
1972 Hillman Avenger GT, the project.

I am no mechanic, would it be worse for the diff if towing a caravan up and down hills ? And make it throw out oil.

The normal failure in the diff for an FL2 is for the under specified nose bearing to fail with a droning from the diff being an early symptom that is easily missed. My diff lasted at least a year before I got it to Bell Engineering and even then it wasn’t definitely diagnosed until Austen took the diff out to check while doing a Haldex service.

Thanks, when reading all the problems it’s easy to become paranoid when you’re not a mechanic

I've checked the breather and its deffinitely attached and intact for its length.

Nodge as far as I am aware the diff and haldex haven't been separated. I was able to change filter, remove pump and replace fluid on the car. I suppose the seal will wear eventually, but I hope it would last longer than 75,000 miles?

Andy

The differential whips up the oil.

And it will turn brown if it has air inside it.

A good (i.e. New) oil will resist this.

Go to 5:45 in the video



Take care

Paul


PS my original Diff Oil at 50,000 miles was chocolate milk brown upon removal but the next day I came back and it was the same color as new oil.