GL-4 & GL-5 Gear Oil Query
Discussion
You could easily write what I know about gearbox oils on the side of a coin, so, looking for some general advice really.
The owner's handbook for my Fiat Grande Punto suggests that only 75w-85 GL-4 oil be used inside the gearbox.
Took my car to a garage (via word-of-mouth) and they drained out what was in there and topped it back up as it was running low.
They've used this: http://www.carlube.co.uk/index.cfm?product=183&... (Carlube EP75w90).
It states in the specification of that oil it covers both GL-4 and GL-5, but I was under the impression that the two were completely separate and, whilst GL-4 can be used in a GL-5 box, it doesn't work the other way around?
So how can a product specify it's both types of oil?
Thanks in advance.
The owner's handbook for my Fiat Grande Punto suggests that only 75w-85 GL-4 oil be used inside the gearbox.
Took my car to a garage (via word-of-mouth) and they drained out what was in there and topped it back up as it was running low.
They've used this: http://www.carlube.co.uk/index.cfm?product=183&... (Carlube EP75w90).
It states in the specification of that oil it covers both GL-4 and GL-5, but I was under the impression that the two were completely separate and, whilst GL-4 can be used in a GL-5 box, it doesn't work the other way around?
So how can a product specify it's both types of oil?
Thanks in advance.
What gets my goat is many of the motor factors where I am carry the Carlube range these days. Previously most carried Comma as their primary selling brand. Now whilst most factors carry other brands too, they do not do so in any real quantity or by full product range. So for example when you require a particular oil for a specific task, the factor only carries their Carlube equivalent, and they are not interested in ordering anything from a more well known up market brand. Mainly because they have to purchase in minimum quantity of more than a litre or 5 litres, which is normally all a customer wants. Then of course there are the sales people that work in manning the motor factors desk and phone lines, and it's unlikely they have a clue about the lubricant you're enquiring about, save for a product range brochure which offers them, and ultimately the customer, very little info. And whilst some might say call the oil company helpline. Try it sometime. Unless you're calling a giant, like Exxon Mobil, chances are you will still not get the info you require as there are no technical gurus available to communicate with from the labelling companies like Carlube and Comma. I mean, does anyone know who's oil is in the Carlube cartons?
Rant over.
Rant over.
Two potential issues:
1) The GL-5 oil will have more sulphur, which could cause problems if you have yellow metal (eg brass or bronze) components in your gearbox.
2) The higher lubricity of the GL-5 oil may reduce the effectiveness of the synchromesh, and give poorer gearchange quality.
1) The GL-5 oil will have more sulphur, which could cause problems if you have yellow metal (eg brass or bronze) components in your gearbox.
2) The higher lubricity of the GL-5 oil may reduce the effectiveness of the synchromesh, and give poorer gearchange quality.
I've received the following information from Carlube's technical department, in regards to the product supposedly covering both GL-4 and GL-5:
"It is possible to meet both these specifications with the same fluid. There was a time when the higher level of extreme pressure additives required for API GL-5 would cause problems in transmissions requiring API GL-4. But as driveline additive technology has developed it has been possible to overcome these limitations.
Typically a GL-5 lubricant will have twice the level of extreme pressure additives in comparison to a lubricant that meets just GL-4. But as the technology is not harmful to the transmissions requiring GL-4 fluid then it is possible to have a product which is suitable for both applications. Obviously it is not the most economic way of meeting the GL-4 specification but there are no performance issues."
None the wiser really.
In the meantime, the garage who did the gearbox oil change have said: "used the oil supplied by our supplier based on the registration number given to them. This was supplied as the correct oil for your vehicle," and then go on to say that if I bring the correct oil to them, they'll change it free of charge.
"It is possible to meet both these specifications with the same fluid. There was a time when the higher level of extreme pressure additives required for API GL-5 would cause problems in transmissions requiring API GL-4. But as driveline additive technology has developed it has been possible to overcome these limitations.
Typically a GL-5 lubricant will have twice the level of extreme pressure additives in comparison to a lubricant that meets just GL-4. But as the technology is not harmful to the transmissions requiring GL-4 fluid then it is possible to have a product which is suitable for both applications. Obviously it is not the most economic way of meeting the GL-4 specification but there are no performance issues."
None the wiser really.
In the meantime, the garage who did the gearbox oil change have said: "used the oil supplied by our supplier based on the registration number given to them. This was supplied as the correct oil for your vehicle," and then go on to say that if I bring the correct oil to them, they'll change it free of charge.
Edited by dankross on Thursday 20th January 12:19
dankross said:
I've received the following information from Carlube's technical department, in regards to the product supposedly covering both GL-4 and GL-5:
"It is possible to meet both these specifications with the same fluid. There was a time when the higher level of extreme pressure additives required for API GL-5 would cause problems in transmissions requiring API GL-4. But as driveline additive technology has developed it has been possible to overcome these limitations.
Typically a GL-5 lubricant will have twice the level of extreme pressure additives in comparison to a lubricant that meets just GL-4. But as the technology is not harmful to the transmissions requiring GL-4 fluid then it is possible to have a product which is suitable for both applications. Obviously it is not the most economic way of meeting the GL-4 specification but there are no performance issues."
To go into such detail, why not just provide you with the spec sheets for the 4 and the 5 so you can make a determined choice - or at least your garage can? "It is possible to meet both these specifications with the same fluid. There was a time when the higher level of extreme pressure additives required for API GL-5 would cause problems in transmissions requiring API GL-4. But as driveline additive technology has developed it has been possible to overcome these limitations.
Typically a GL-5 lubricant will have twice the level of extreme pressure additives in comparison to a lubricant that meets just GL-4. But as the technology is not harmful to the transmissions requiring GL-4 fluid then it is possible to have a product which is suitable for both applications. Obviously it is not the most economic way of meeting the GL-4 specification but there are no performance issues."
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