Thread: Oils that are NOT safe for a series 2/3 gearbox/transfer?

Some oils apparently attack bronze - so the easiest way is to pick an oil you like and ask the manufacturer if it is safe on bronze.

I contacted Penrite about their oil and they assured me it was fine to use in my S1 - see below.


Hello Charlie,
Thank you for your enquiry.
We currently recommend Mild EP Gear Oil for the Transmission, Transfer Case, Front and Rear Differential of your vehicle.
You could also use Hypoid 80W90 for your front and rear axle. Both
products are perfectly safe with copper / bronze components.

Regards
David Baldie
Senior Chemist
Penrite Oil

Some GL5 oils don't use buffered sulphur EP additives, therefore they can react with yellow metals and corrode them.

Any GL4 oil will be OK, they only have 2/3 the additive levels of a GL5.

Basically if an oil says it's a transaxle oil it should be OK as it's designed for gearbox and diff use, eg. Castrol Multitrax or Castrol Syntrax.

Anything that is dual rated GL4/5 should use buffered sulphur and be safe.

Any diff oil that advertises that it uses a borate rather than sulphur based EP additive aould be OK.

Ultimately, if you can find a copper corrosion number on a TDS/PDS, 1a or 1b are absolutely safe.

I'd try a 75W-90 as it should shift better in cold weather.

Originally Posted by rick130

Any GL4 oil will be OK, they only have 2/3 the additive levels of a GL5.

While that may be true of GL4, it does not mean that the container of oil you buy is actually a GL4. Many so called GL4 oils are sold as being equivalent to GL4 and GL5. In those cases, the GL4 oils are not safe to use in your older transmission because they are in fact GL5 oils. Recent developments have also been formulated specifically for limited slip differentials, these can be damaging to older transmission and differentials.

The problem with these oils is that the chemicals they use to improve slip and prevent corrosion in newer components are able to be absorbed into the porous copper based metals. This can occur because the molecular chains are smaller than those in yellow metals. While that is not a real problem, the issue is that when the oil then achieves sufficient heat (normally up to about 100-130ºC) the absorbed molecules expand and cause the soft metals to fracture. Other than that, the "modern" formulations are designed to protect against different kinds of wear (the metal surfaces meet in different ways).

Shell now have a new product that has been developed specifically to resolve these issues and is intended to be a replacement for EP90, which is no longer available. It is called Shell Omala 320. I have spoken to the industrial oils specialist at Shell. He explained this and other things to me about it.

Here is some info on it.

Here is the technical specs sheet.

I have just bought a 20l container, the smallest they come in.

Alan

LSD fluids should never be used in a synchro gearbox. Full stop. end of story.
The friction modifiers will work against decent synchro engagement.

If it's an LSD fluid it will state it on the bottle.
I don't think anyone has even suggested that they be used ?

BTW, everyone has in their heads GL5's eat yellow metals and can't see past it......
There are plenty of dual rated fluids that are fine.
I thought I explained that, but obviously not well enough........

BTW, that Omala fluid looks like an industrial, not automotive gear oil ? and can you find me a TDS as that's an MSDS.

FWIW, I ran GL5 oils for years in my series boxes and t-cases. Every time I pulled the box or t-case down (to repair or upgrade components) I did not notice any accelerated wear/corrosion.

IME the series box is so weak and has so many design issues, it needs all the help it can get from lubricants, so I would prefer the improved lubrication provided by a GL5 oil.

Originally Posted by isuzurover

FWIW, I ran GL5 oils for years in my series boxes and t-cases. Every time I pulled the box or t-case down (to repair or upgrade components) I did not notice any accelerated wear/corrosion.

IME the series box is so weak and has so many design issues, it needs all the help it can get from lubricants, so I would prefer the improved lubrication provided by a GL5 oil.

The same with a Rover (not Sals) diff.

There's no way on earth I'd run a low EP fluid in one, just not enough protection IMO.