Front Diff Work?

Hello All,

I just drained the oil from my front diff. There was about a centimetre of crystal clear water in the bottom which came out first, followed by a horrible sludge with the look and feel of melted Cadburys! Does this sound reasonable (I have no idea what to expect)?

I wanted to take a quick look inside the front diff whilst it was drained if for no other reason than to familiarise myself with it. Having looked at it though it seems the only way to access it is from the rear where the prop shaft enters it which looks like it may lead to yet more jobs (I was hoping the front would just have a nice cover I could remove to look in and nowt much else). Is my understanding correct and if so is accessing the diff from its back much hassle or not?

I don't think you have to much to worry about.
Probably just a bit of water managed to get in.
Re fill it with clean oil and you should be ok, I know this will sound like a bit of a faff, but fill it take it for a good drive, then drain it off again and re fill.
Check the axle breather pipe for any signs of cracks

That black pipe running down the radius arm to the top of the axle.
Check him for cracks, or even if its present, it should trail off above the chassis.
If it aint present, short or hanging down, that maybe why there is water in yer axle.
Have a look over the axle for any cracks or damage.
If its all appears sound, fill with clean oil



Busters pic BTW

It may well be worth popping the diff off to clean out all the mayonnaise generated by the oil and water. I'm afraid it's not the simple job you hoped for but dismantling the axle might be necessary to work out where the water came from. There's an oil seal where the prop drive flange goes in and a couple in the ends of the axle case. There's also a breather which might be jammed open. What state is the lubricant in the swivels like?
To take the diff out first remove the propshaft, pull out the driveshafts (you can cheat by unbolting the whole swivel where it joins the axle case after removing the steering rods - there should be enough movement in the brake hoses) unbolt the ring of bolts around the diff and then pull it backwards. Put a trolly jack underneath to support it 'cos it's heavy. You'll need a new diff gasket and some instant gasket for where the swivels join the axle case.
Or you could just refill, run the vehicle for a few miles, drain and fill again.

Some older vehicles don't have a breather pipe - there's a valve that vents to atmosphere instead.

The only way to inspect the diff is to remove it from the axle,you won't see inside the diff by taking the prop off.
If you've got water in the axle casing it would be advisable to drain and refill the swivel housings too.

The oil from the swivel housings was similar to that in the diff (that is minging and a melted chocolate colour and consistency). I started taking them apart originally as the bearings failed MOT.

My axle has the breather valve - what can I do to inspect that/check it's integrity? ...or should I just replace?

The rubber washer on the diff drain plug was useless - oil leaking heavily and it perished as I removed it - and when I first bought the car I had a childish desire to fly through deep puddles so perhaps I have forced the small amount of water in up through the bottom???

I think I will try to avoid removing the diff completely for now based on that feedback - though add it to my longer term list of jobs.

I have the swivels off/apart and intended to replace all perishable parts as I reassemble them. I'm not sure exactly what I need but I got some bits which I hope will cover it as per some feedback on here and what Autopost (Wimbledon) recommended. In addition it sounds like I also need to confirm the breather valve is good and possibly check the oil seal from the propshaft, Oxides, can I check/change that oil seal easily or again is that part of the bigger job only?

Lastly, is my breather valve option okay or should I consider fitting a breather pipe instead for future?

Thanks for such helpful advice so far.

Andy.

P.S. This work is being done in Bracknell, should anyone want to pop round and be foreman - liquid refreshment would be provided.

Also, what do I fill Diff and Swivels with?

Not unusual to have a little water in the diff (landrovers live for swimming).

The diff/swivel oil sounds as if it was well passed its usefullness.
Mine wasn't quite as bad as yours sounds, but was a very dark caramel colour. The swivel oil was blackened.

A lot of work to take the diff off, just to have a look, unless you've got access to an endoscope. You can assess backlash on the diff by sticking transfer box in 2WD with hubs engaged (if free wheel hubs) and check its not excessive. Mine has about 10-15 degrees of backlash, but still works fine!

I think I'd be tempted to fill the diff/swivels with some thinner oil (or perhaps EP90 thinned with some diesel/parafin) to help clean everything up in there. A bit like using a flushing oil.
Give it a bit of a gentle run about, then drain/refill with EP90 oil upto the correct level in both diff and swivels.

Check all your breathers and the axle for air/liquid tightness.

Given the state of your front diff oil, I'd then treat your rear to the same fresh oil.

Mark

The breather valve should ungunge if washed in solvent (petrol will work) but remote breather pipes are probably a better idea. EP90 (or 80/90) for diff and swivels. Propshaft flange oil seal can be replaced with the diff in situ. The drain plug should have a copper washer not rubber!

oxides said:

The breather valve should ungunge if washed in solvent (petrol will work) but remote breather pipes are probably a better idea. EP90 (or 80/90) for diff and swivels. Propshaft flange oil seal can be replaced with the diff in situ. The drain plug should have a copper washer not rubber!

Click to expand...

It defo had a rubber washer which fell out of it. I will replace with the correct copper one.

The breather unscrewed okay and looked fairly tidy though it has been painted externally so I'm not sure if that's stopped any components moving as they should. The ballbearing from the inside looks fine but nothing seems to move or be unsealed from the outside (so has the donk before just painted the whole thing and seized it up?). I may just replace it for the sake of a quid especially as I don't know what a working one behaves like if overhauling mine.

I think I'd like a breather pipe in case of wading in the future: Job # 10992 added to the list!