Diff oil

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HeywoodFloyd

HeywoodFloyd

Active Member
Posts
282
Location
Essex, UK
Yep... another thread about diff oil.

Sorry, I'm a newbie and have been working on my old 1987 90 for only a few weeks now. But I'm a fast learner. The rear diff was leaving horrible gue on the drive, some research pointed me to a blocked breather and, in turn, a blown seal. I've sorted both now, but it looks like the oil level is low - nothing comes out if I open the refill thingy.

The tonnes of posts on here tell me that EP90 GL4 is the way to go, but GL5 is probably also ok if I'm only using it on the diff and nothing else.

Anyway, GL4 is fine, but rather than just posts and post and more posts about the type, does anyone have a preference or recommendation about a specific brand/product? I'm never one to just go for the cheapest I can get my hands on... but I'm no expert on choosing something like this.

Who's used what for this?
 
HeywoodFloyd said:
does anyone have a preference or recommendation about a specific brand/product?
Click to expand...
I use Castrol Syntrax Universal Plus 75W/90. It meets GL4 and GL5, is a synthetic & can be mixed with mineral oils. Also ok with conventional oil seals. About £18 a litre from Opie Oils (they sell on flea bay). I like it as it can be used in all my transmission items. Google / ask jeeves and form your own opinion.
 
HeywoodFloyd said:
Yep... another thread about diff oil.

Sorry, I'm a newbie and have been working on my old 1987 90 for only a few weeks now. But I'm a fast learner. The rear diff was leaving horrible gue on the drive, some research pointed me to a blocked breather and, in turn, a blown seal. I've sorted both now, but it looks like the oil level is low - nothing comes out if I open the refill thingy.

The tonnes of posts on here tell me that EP90 GL4 is the way to go, but GL5 is probably also ok if I'm only using it on the diff and nothing else.

Anyway, GL4 is fine, but rather than just posts and post and more posts about the type, does anyone have a preference or recommendation about a specific brand/product? I'm never one to just go for the cheapest I can get my hands on... but I'm no expert on choosing something like this.

Who's used what for this?
Click to expand...

It will be quite happy on mineral 90 weight, that is what it was designed to use. Used it in all my old landrovers, just the oil merchants own brand stuff.

If you want to spend the extra money, and as he says, compatibilty with modern vehicles, the expensive stuff will do no harm.
 
GL4 is only really needed on the series land rovers and thats always in debate, the 90 models onwards will be happy on anything really and I mean anything.
I would personally use the cheapest bulk 80/90 75/90 straight 90 I could get 18 quid a litre is madness.
Might be different with the tdci?

One of many on ebay 3.70 per litre delivered, http://www.ebay.co.uk/itm/Smith-All...547920?hash=item563a9ce3d0:g:fQAAAOSw-YVXmHsd
Works out even cheaper per litre if you buy 20/25 litres and if you are keeping the car its well worth buying in bulk.
The same oil works just fine in the transfer box as well.
 
As far as I know the transmission components on the tdci built to the same engineering standards as any other defender and its ancestors. They still specify mineral oils for the front and rear differentials where a GL4 or GL5 can be used, with changes at 50k miles. Castrol Syntrax is specified for the transfer box, with changes at 50k miles. There is an odd specification for the gear box oil but I researched and found that the Castrol Syntrax meets the spec, this is a "fill for life" (deemed to be 125k miles so I don't see this as "life"). I always change all lube well in advance of the mileage intervals as a matter of personal preference. One diff has currently got mineral oil in and the other a mix of mineral and Syntrax because thats what I had on the shelf at the time, transfer box has Syntrax, gear box still has the factory fill which I will change at 50K miles or next summer whichever comes first (aint gonna do it on the driveway now the cold wet sh1t weather has arrived). As I understand it the synthetic oils have superior molecular structure compared to minerals and therefore have a much longer useful life hence the increased service intervals.
 
Wimblowdriver said:
As far as I know the transmission components on the tdci built to the same engineering standards as any other defender and its ancestors. They still specify mineral oils for the front and rear differentials where a GL4 or GL5 can be used, with changes at 50k miles. Castrol Syntrax is specified for the transfer box, with changes at 50k miles. There is an odd specification for the gear box oil but I researched and found that the Castrol Syntrax meets the spec, this is a "fill for life" (deemed to be 125k miles so I don't see this as "life"). I always change all lube well in advance of the mileage intervals as a matter of personal preference. One diff has currently got mineral oil in and the other a mix of mineral and Syntrax because thats what I had on the shelf at the time, transfer box has Syntrax, gear box still has the factory fill which I will change at 50K miles or next summer whichever comes first (aint gonna do it on the driveway now the cold wet sh1t weather has arrived). As I understand it the synthetic oils have superior molecular structure compared to minerals and therefore have a much longer useful life hence the increased service intervals.
Click to expand...

They are welcome to run it for 50k if they like. I change mine every year, always have done. :)
 
Wimblowdriver said:
Agreed, seems too long to me. Changed my diff oil at under 24k, transfer box at 28k, old oil was still looking good though.
Click to expand...

With a vehicle that doesnt do many miles, ans spends a lot of time stood in a damp climate, condensation in the oil is the main issue.

Detroit Locker are pretty hard on the diff oil, visibly darker and more opaque after a year, and they get clunky if the oil isnt good.
 
Turboman said:
They are welcome to run it for 50k if they like. I change mine every year, always have done. :)
Click to expand...


Same here, Im not really sure why as if you dont off road your motor the diffs going to get a very easy life, last year my 90 did 200 miles between mots:D
The D3 auto g/box oil was meant to be changed at 150k!
 
Forgot to say if you search you can find discount codes for smith and allen oils like the one I linked to on ebay.
 
lynall said:
Same here, Im not really sure why as if you dont off road your motor the diffs going to get a very easy life, last year my 90 did 200 miles between mots:D
The D3 auto g/box oil was meant to be changed at 150k!
Click to expand...

I off road every time I go out, I live a mile from the made road. I never drive through deep water, though.

And for some reason, as I said earlier,Detroits are hard on the oil. I always used to do it on standard axles as well, though.

Mr S1 said:
I change all the oils annually - just good practice. Easy to do, so why not as part of routine maintenance.
Click to expand...

Exactly, and the quantity that comes out, and if there are debris in it, is a useful diagnostic tool.
 
Boring fact, did you know D3/4 front diffs take 0.60 litres of oil and the rear just a litre and its meant to be good for 150k and diffs cost 5/600 quid each!

I think every rover axle diff i have bought has been roughly 40/50 quid and Ive given some series ones away as they are virtually worthless.
 
I just brought straight 90 gear oil for my diffs, comma I think, I put it in a garden sprayer I modified to make filling easier and cleaner. I change it yearly
 
HeywoodFloyd said:
Yep... another thread about diff oil.

Sorry, I'm a newbie and have been working on my old 1987 90 for only a few weeks now. But I'm a fast learner. The rear diff was leaving horrible gue on the drive, some research pointed me to a blocked breather and, in turn, a blown seal. I've sorted both now, but it looks like the oil level is low - nothing comes out if I open the refill thingy.

The tonnes of posts on here tell me that EP90 GL4 is the way to go, but GL5 is probably also ok if I'm only using it on the diff and nothing else.

Anyway, GL4 is fine, but rather than just posts and post and more posts about the type, does anyone have a preference or recommendation about a specific brand/product? I'm never one to just go for the cheapest I can get my hands on... but I'm no expert on choosing something like this.

Who's used what for this?
Click to expand...

GL4/5 in the diffs is fine.
GL4 only in the transfer box. Parts guys argue that GL5 is a direct replacement for GL4 - it is not.
 
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