What is Hypoid oil?

[Malcolm]

My workshop manual says I need to use Hypoid oil in the rear axle. What is it, and by what name do I ask for it at the shop?

And what oil should I be using in my gearbox?

Thanks!

[minor_hickup]

Hypoid oil is for gears. I can't tell you what makes it special. For the rear axle use EP90, if your car is a later one, use 20w50 motor oil in the box. I think sidevalve boxes used EP90 as well.

[bmcecosse]

Hypoid - is the gear form on the rear axle drive gears. Extreme Pressure 90 oil has additional additives to fend off the high rubbing forces between the hypoid gears.

[Welung666]

And it stinks to high heaven

Lee

[rayofleamington]

And what oil should I be using in my gearbox?

For a Minor 1000 - don't use EP80 or EP90 in the gearbox (even if it says 'for axle and gearbox' on it
The gearbox should have 20/50

[minor_hickup]

And it stinks to high heaven

Lee

Yeah it does, one of the few smells that make me want to throw up. This should go into useful tips really, wear a mask when using it!

[lowedb]

As mentioned above, Hypoid is the name of the gear form. If I remember right, it's a curved tooth that means the engagement and disengagement is smoother and you get less noise. The problem is that most of the drive takes place on a very small point of contact meaning you need the extreme pressure (EP) oil to stop it getting destroyed quickly and therefore destroying the hypoid gear.

Regarding the smell a Friend of mine got fed up with a colleuage at work smoking while they were working and quote 'stinking the place out', so he got a spray bottle of gear oil (smells like cats p) and sprayed his 'friend' every time he lit up.

[bigginger]

What does the sprayer's epitath read?

[woo]

I've got an old copy of a Castrol book called 'Car Care' It deals with lubrication. Under the topic 'Hypoid Gears' it says the following:

"The hypoid final drive, which is a modified spiral bevel in which the pinion is set below the centre of the crown wheel, enables the propeller shaft to be lowered, thus largely obviating the necessity of a tunnel in the floor of the rear compartment. Because of this out-of-centre location of the pinion the tooth action is a sliding one rather than the rolling motion of the normal spiral bevel but this sliding is accompanied by severe local pressures. The combination of high pressures and high sliding velocities has imposed such severe conditions on the lubrication oil that it has been necessary to evolve special lubricants to cope with them. While these are in fact powerful extreme pressure lubricants, they have become known as hypoid lubricants and it is essential to use only hypoid oils for hypoid gears."

So now I know what a hypoid gear is!

[Willie]

Hypoid oils also have extreme 'clinging' properties so that there will always
be a film of oil on the pressure areas even after a long period of idleness.

[Cam]

What does the sprayer's epitath read?

Here lies a hero?

[woo]

What does the sprayer's epitath read?

Perhaps it said:

"Here lies a good sprayer but a poor speller"

[bigginger]

Quite right - I deserved that

[bmcecosse]

I like the smell of EP 90 - it's one of the characteristic smells of older cars!

[Onne]

really. I prefer cat wee

[Rasputin]

It`s a bit too thin for the rear axle;-)