Axle Oil

[cbalme]

Hi everyone, I know this question has been asked many times but I can't seem to find an answer. I'm about to fill my axles with oil but not sure what to use.

I have some 80w-90 API GL5 Hypoid Gear Oil on tap at home but I read somewhere that may cause problems. Is that alright to use or should I go get some other stuff?

Thanks

[red90]

That is what you should use.

[mepham55]

The original spec for the Land Rover gear oil is GL4, which is hard to find now. Essentially it is “yellow metal” safe meaning it doesn’t have the sulphur additives of GL5, which is indicated by the extreme pressure rating on the bottle. Your diffs don’t have any bronze in them so any generic 90w is ok to use. For your transmission, Royal purple and Amsol make a “yellow metal safe” gear oil that’s good for your gearbox, transfer case and overdrive. That said, I’ve used GL5 in tansmissions for years and never really noticed any accelerated wear on the bronze parts! I think it’s more important just to make sure there’s oil in there, no matter what it is!

Matt

[swamijake]

I concur. I use any old gear oil in the axles and Redline MTL in the transfer case and transmission.

[cbalme]

Thanks for clearing up my concerns. I was pretty sure there weren't any yellow metals in the diff when I took it out. I'll just use what we've got then get some of the pricey oil for the gearbox.

[red90]

Without getting into the whole thing....there is not actually a copper corrosion concern with GL5 gear oils unless you are using a bottle of oil made in the 70s.

There are a couple of reasons it is not a good idea with synchronizers, but it is not because of corrosion. So, gear oil is fine as long are there are no synchros. If there are synchros, it is best to use a manual transmission fluid or engine oil of a suitable viscosity.

[swamijake]

I read that most (ostensibly all) of GL-5 oils now use a borate stabilizer that prevents the rapid degradation of yellow metals, but I suspect there might still be a problem with GL-5 oils that aren't changed on a regular basis. Apparently it was the sulfur in the EP package that combines with copper to form the very hard copper sulphide that then acts like sand, pitting and ultimately wrecking the yellow metal components. The borate stabilizer prevents this, BUT the sulphur when run hot with moisture present over time oxidizes, ultimately forming SO3 which reacts with water to form sulphuric acid, allowing a different attack path.

Does it matter if you change your gearbox oil regularly? No.
Does it matter if you hardly ever change your gearbox oil and drive hard? Probably not, but an extra 30$ when changing the transfer box oil for a synthetic GL-4 is a price I'll pay.

Plus I swear it shifts better, has more power and gets better mileage when I use more expensive oil.......

[cbalme]

Hi, sorry to bother you all about Oils again but it's time to fill my Gear and Transfer Box. I've got some Duratran in a drum that's rated for API GL4 so I might use that.

The Haynes Manual says to use Hypoid Gear Oil, Viscosity SAE 90EP, to API GL4 so it must be the right stuff.

https://i.imgur.com/dBvaD2cl.jpg

[swamijake]

Pretty sure that is exactly what you want

[Greg S]

There is more information on this at www.vanislelandrovernetwork.com

Open the "LR tech info" menu and click on "GL4 gear oil"