Gearbox oil - accidentally put GL4

[nunesaf]

Hi,

By mistake, I got 80w-90 Castrol oil and changed the gearbox oil over the weekend. Today when changing the oil on the bevel, I realised that I have GL4 in the gearbox. Should I replace it with GL5 or doesn't this do any harm?

Thanks

 

[Timolgra]

"GL5 is a different spec, and is not 'backwards compatible' with GL4.

GL5 gear oil is a lubricant with very high extreme pressure performance needed for Hypoid gears where sliding and rolling contacts operate under very high loadings.

This is achieved by incorporating high concentration of sulfurized additives. The downside to such high sulfur in oil is it tends to corrode yellow metals, so can ruin parts like brass synchronizers and some bushings. So any equipment needing GL5 performance is designed taking this limitation of the lubricant into account.

GL4 oils are much more friendly to yellow metals, and so are used in equipment where such high load sliding-rolling contacts aren't present. The designers of such equipment aren't as limited in the use of brass parts.

So the bottom line is that if your equipment calls for GL4 it probably doesn't need GL5 performance, and you may be asking for trouble down the line if you use a lube it wasn't designed for."

 

[Comfy Old Boots]

"GL5 is a different spec, and is not 'backwards compatible' with GL4.

GL5 gear oil is a lubricant with very high extreme pressure performance needed for Hypoid gears where sliding and rolling contacts operate under very high loadings.

This is achieved by incorporating high concentration of sulfurized additives. The downside to such high sulfur in oil is it tends to corrode yellow metals, so can ruin parts like brass synchronizers and some bushings. So any equipment needing GL5 performance is designed taking this limitation of the lubricant into account.

GL4 oils are much more friendly to yellow metals, and so are used in equipment where such high load sliding-rolling contacts aren't present. The designers of such equipment aren't as limited in the use of brass parts.

So the bottom line is that if your equipment calls for GL4 it probably doesn't need GL5 performance, and you may be asking for trouble down the line if you use a lube it wasn't designed for."

Hiya,

Just wondering but...

"GL5 is a different spec, and is not 'backwards compatible' with GL4.

...what does that mean exactly? Will flushing it and refilling with GL4 not get rid of GL5? Perhaps followed by a spirited run, making progress and all that malarkey...

 

[nunesaf]

So the bottom line is that if your equipment calls for GL4 it probably doesn't need GL5 performance, and you may be asking for trouble down the line if you use a lube it wasn't designed for."

Well, I think BMW specs are GL5

Maybe it's better to replace by GL5 then.

 

[Timolgra]

Well, I think BMW specs are GL5

Maybe it's better to replace by GL5 then.

you won't have caused any damage at all.

 

[JoeC]

Personally, I would keep the GL4 in there for a couple of hundred miles of so and then drain and put in GL5. Think of it as a flush.

 

[nunesaf]

Personally, I would keep the GL4 in there for a couple of hundred miles of so and then drain and put in GL5. Think of it as a flush.

Thank you all for the suggestions. I think that's what I'll do, keep it for a while and then change back to GL5.

 

[MattW]

There isn't much gearbox oil and it has a hard life. For the few pennies it will cost I'd drop the GL4 and replace it with GL5.

 

[DrAlf]

I accidentally used GL4 oil in an 1150 gearbox a few years ago. The gearbox failed completely locking the rear wheel about 1000 miles later. May or may not have been related but I always make sure I use GL5 now. If I were you, I’d change it ASAP – not in a few hundred miles.

 

[sockpuppet]

Do you know what went wrong in the gearbox?

 

[motobiker]

Do you know what went wrong in the gearbox?

He used the wrong bloody oil!!


I can't believe (no.. actually I can) that this question is being asked. A litre of GL5 is what? £9.99 from Halfords... and probably available elsewhere at a lower price.

£9.99

How much is a replacement gearbox? How much is a replacement Bike if the thing seizes and throws you off?


I love this forum.

 

[Stewart H]

He used the wrong bloody oil!!


I can't believe (no.. actually I can) that this question is being asked. A litre of GL5 is what? £9.99 from Halfords... and probably available elsewhere at a lower price.

£9.99

How much is a replacement gearbox? How much is a replacement Bike if the thing seizes and throws you off?


I love this forum.

+1, drop it out, let it drain overnight and refill with the proper stuff, it will cost as much as less than half a tank of fuel or a couple of beers
Stewart

 

[nunesaf]

He used the wrong bloody oil!!


I can't believe (no.. actually I can) that this question is being asked. A litre of GL5 is what? £9.99 from Halfords... and probably available elsewhere at a lower price.

£9.99

How much is a replacement gearbox? How much is a replacement Bike if the thing seizes and throws you off?


I love this forum.

Surely the cost of the oil is not a driver here. I find it a bit difficult to understand that GL4 would cause a collapse in the gearbox. However if your gearbox is designed with GL4, GL5 could case damage due to the extra additives it has.

Anyhow my lovely GS is not running now, I'll get on the car and drive to my nearest Halfords on Saturday and job done

 

[MattW]

Surely the cost of the oil is not a driver here. I find it a bit difficult to understand that GL4 would cause a collapse in the gearbox. However if your gearbox is designed with GL4, GL5 could case damage due to the extra additives it has.

You're right, the cost isn't (or shouldn't be) a driver. Think about the design of the engine and gearbox.

The engine generates pretty high torque and the input shaft spins at crank speed. Hence the torque and tooth / bearing loadings are much higher than in a 'normal' unit construction bike gearbox where the box is deliberately spun at higher than crank speed to give it and the clutch an easier time (and to allow it to be designed down to a size and weight).

So, due to the design and materials present in the gearbox a GL5 grade lubricant is specified.
So use one - seems simple to me...

(or use chipfat and keep people like Steptoe in business )

 

[motobiker]

I wasn't implying that cost was a driver.. my point was simply that replacing the incorrect oil thats in the gear box.. with the correct spec will cost you at most £10.

People get so uptight on this forum about which ENGINE oil to use.. mainly because they see the manual which isn't really specific, it just gives various options for different grades for the prevalent weather conditions. In my manual it gives 3 types that are most appropriate for our weather here in the UK. and so.. we see the constant 'which is best?' questions being asked.

With the gear box and FD 'gear oil' BMW ARE very specific. they do not say.. you can use this.. or that...

they say.

"Brand name hypoid gear oil API class GL 5"

You can choose to ignore that.. at your peril.

 

[Timolgra]

I wasn't implying that cost was a driver.. my point was simply that replacing the incorrect oil thats in the gear box.. with the correct spec will cost you at most £10.

People get so uptight on this forum about which ENGINE oil to use.. mainly because they see the manual which isn't really specific, it just gives various options for different grades for the prevalent weather conditions. In my manual it gives 3 types that are most appropriate for our weather here in the UK. and so.. we see the constant 'which is best?' questions being asked.

With the gear box and FD 'gear oil' BMW ARE very specific. they do not say.. you can use this.. or that...

they say.

"Brand name hypoid gear oil API class GL 5"

You can choose to ignore that.. at your peril.

Nobody's suggested otherwise

 

[nunesaf]

I wasn't implying that cost was a driver.. my point was simply that replacing the incorrect oil thats in the gear box.. with the correct spec will cost you at most £10.

People get so uptight on this forum about which ENGINE oil to use.. mainly because they see the manual which isn't really specific, it just gives various options for different grades for the prevalent weather conditions. In my manual it gives 3 types that are most appropriate for our weather here in the UK. and so.. we see the constant 'which is best?' questions being asked.

With the gear box and FD 'gear oil' BMW ARE very specific. they do not say.. you can use this.. or that...

they say.

"Brand name hypoid gear oil API class GL 5"

You can choose to ignore that.. at your peril.

Thank you all for your sound and sensible opinions that are being followed.

Regards

 

[Kenny]

Drain GL4 and replace with recommended GL5, fully 100% sorted

 

[nunesaf]

Drain GL4 and replace with recommended GL5, fully 100% sorted

Job done! GL4 out and GL5 put back in

Thank you all for your help, very useful recommendations otherwise I would have damaged my bike. A big big thanks!

 

[sockpuppet]

He used the wrong bloody oil!!

I get that. What I was trying to work out was if the oil caused it.