whats the difference between gear oil and engine oil?

i went out and stupidly bought gear oil still 10w 40 though..... so what the difference between gear oil and engine oil of same 10w40?????

Might be differant additives etc...if i was you, i;'d take it back and ask for it to be exchanged, dont chance it

Matt

[embee]

10W-40 is an unusual spec for a gear oil. What exactly do you have, make etc??

The principal differences between engine type oils and "extreme pressure" or EP gear oils is the ability to withstand very high contact pressures as seen in car final drives (axles) etc. These are usually referred to as EP or sometimes "Hypoid" or similar. Additives used for this purpose don't usually take kindly to dealing with things like blowby gas and condensation etc, similarly the additives often aren't catalyst/lambda sensor friendly, and can even attack certain bearing materials.

Some gearboxes, such as integrated bike engine/gearboxes, are designed to be able to live with an engine type oil without the need for extreme pressure additives. Engine oils still contain additives to protect against scuffing at high contact pressure places like cams and followers which will also protect lightly loaded gears.

[yorkie_chris]

Completely different additive pack, I've never actually seen 10w40 gear oil, its usually EP80/90, but as mentioned it won't be designed to deal with condensation or combustion products, as gearboxes don't see these things. Effects on seals and such are possible, but nobody knows for sure.
It won't make your engine sieze up on first run, but won't do it any good.

Don't chance it, It's only a tenner or so for some decent oil.

A wet clutch wont like it.

Engine oils are designed to cope with combustion products (acid fighting, soot handling etc.) and much higher temperatures in the piston / ring pack area. If contact stresses are not too high they can also lubricate gears (like in the SV).

Gear oils are designed to cope with very high contact stresses between gear teeth.

There are multigrade gear oils available, including 10W-40, but they won't have the right additives to cope with the engine environment.

Soooooo ....Don't use a gear oil in the engine.

Cheers Keith