Gearbox and overdrive oil

[mowerman]

Having completed the rebuild of the gearbox and o/d unit I need to fill it with oil. Mr Haynes reccomends Hypoid SAE 90EP. I think this is wrong? Somewhere in the back of my mind a little voice says it should be a straight 90 not an EP grade? Are the voices correct or am I going mad :-/

[Richard B]

Check with Canleys, I know they use to sell the correct oil. I think its either 75W-80 GL4 or 80W-90 GL4. Must be a GL4, as GL5 is too agressive and attacks the phosphor Bronze components.

EP90 is okay for topping up and I assume, it was intended to be used as the gearbox components wore.

ps. You can get a Semi-Synthetic GL4.

[Deleted User]

EP 90, stop worrying about all the other rumours.

If you want really to go mad, go buy some Mobil1 gearbox oil (fully synthetic) or Motul which is even better.

A good synthetic oil will take very good care of one of those gearboxes and the overdrives work fine on all those things

(attack phosphor bronze indeed!!!first time I ever heard such rubbish!!)

Cheers

GT

[heraldcoupe]

[quote by=GTEVO link=Blah.pl?b=hervit,m=1158306296,s=2 date=1158847566]
(attack phosphor bronze indeed!!!first time I ever heard such rubbish!!)
[/quote]

GL5 has properties which make it aggressive towards yellow metals, acknowledged throughout the automotive industry. In addition to classic applications, more recent (1990s) cars I've owned have manufacturers literature specifically warning against the use of GL5 spec oils in their transmission systems.
If this really is the first time you've heard "such rubbish", I suspect you've not spent much time around old cars.
Cheers,
Bill.

[Deleted User]

oh really?

So what are the parts that fear so much in that transmission??

The syncro rings are in fact made of Brass using a Borg Warner patent, just like any modern gearbox.
The thrust washers are also made of STEEL faced with brass.....as is also used in many modern gearboxes. The thrust washers used in the back of the overdrive are sintered brass and are used in VERY many Ford and volvo cars until very recently

If there was such a lot to worry about I'm sure I would have heard of it by now...It's my job YER KNOW!!

[heraldcoupe]

No, I DON'T know it's your job. I don't know who you are or what you do, or have any reason to place your opinion above that of anyone else. The GL4 specification requires lower levels of sulphur than GL5. Some manufacturers specifically warn against using GL5 oils, my own "modern car" experience being with a mid-1990s VW Passat. All factory literature relating to that car is quite specific in which models should use GL4, and which can tolerate GL5.
My wife Karen spent many years as a professional development chemist for a well known lubricants manufacturer. Her experience isn't in the automotive sector, however she is quite conversant with the properties of the additives you dispute. She says:

It is my understanding that EP type gear oils contain active sulphur. This acts by chemically changing the surface of a metal into the metal sulphide, which is a solid lubricant. Yellow metals (copper containing alloys) are attacked by sulphur. When I worked for the world's largest supplier of metalworking fluids we had to test any new formulation for copper corrosion properties in order that the copper alloy moving parts of the coolant pumps were not dissolved by the metalworking fluid. Many of the additive companies would have you believe that their sulphur containing extreme pressure (or EP) additives would not corrode copper, but in my experience anything over about 30% sulphur content in the additive (used at about 5% concentration in the formulation) would make the product fail a copper corrosion test. Bear in mind that I am talking about soluble metalworking fluids, where the test is carried out at the in use concentration of between 2 and 5% oil in water. You can now see why I am concerned about putting active sulphur anywhere near yellow metal bits of my gearbox.

Cheers,
Bill (and Karen)

[Deleted User]

As a maintenance manager of a large plant we have some very big very expensive gearboxes containing phosphor bronze components samples are taken monthly one of the  contaminates mionitored is  sulphur.....please respect other people opinions GTEVO and dont be so aggresive we are not that sort of club..be polite

[Nick Jones]

There's been alot of information and mis-information about on this subject.  Must admit that I'm not entirely sure which is which.

As I understand it the GL5 oils should not cause problems with gearbox parts - and that fits with my own experience as I have used GL5 oils in both Herald and Vitesse for some years without any problems.

The one that people seem to get most excited about is the thrust washers in the diff (those that have metal ones rather than fibre).  But even then I'm not convinced it's really a problem.  Had this discussion with an ex-colleague who had previously been a lubrication specialist with Shell (so he should know) and he reckoned that in the early days of GL5 there may have been some truth to it with some brands and some specific yellow metal alloys, but he was confident that it would be not a problem with oils purchased today.

Must admit that I would still be a little wary of putting GL5 in a Triumph diff although I suspect I have in the past before I had heard anything about this!

There was an excellent thread with a good technical link on the TTN forum a while back - will post it when I find it............

Nick

[Deleted User]

Just had a look at the spec on castrols range they have a GL5 for diffs and a GL4 for gearboxes

[rayman]

hope this helps, in the past i have many 60:s cars  with & without overdrive.
I recomend a good quality engine oil as ep90 is too thick & cause the overdrive to stick. {ihave had this problem many atime aspecially on sunbeams] i changed iol for engine oil & was ok.
Roots recomended engine oil for there cars with overdrive.
lets face it the engine oils now can cope a lot better thn they did in the 60,s&70,s.
I am a machanic  that worked on these car in the in the 70,s.
altho i did not work on herald  the princible is the same if a oil can cope in one gearbox it can cope in any  all gearboxesare the same. {rover even recomended chaging manual gearbox oil in SD1,s & putting auto fluid in to make easyer gearchangin. later BMW all have auto fluid in there manual gearboxes}
Hope i havent confused anybody but hope this is of some help. ;)

[Deleted User]

Well said Karen!

[Freebird]

Steve

Back to your original question. I have just recieved a genuine Vitesse Mk2 owners handbook and this is the list of lubes recommented for the gearbox/overdrive unit.

Over 30 F (0 C)
BP Gear oil SAE 90
Castrol Hypoy
Duckhams Hypoid 90
Esso Gear oil GP 90
Mobilube GX 90
Fina Pontonic MP SAE 90
Shell Spirax EP 90
Texaco Multigear lubricant EP 90

For under 30F all the same, but 80 instead of 90

It also says API designation GL4, but of course GL5 didn't exist back then.

Cheers

Glen.