EP gear oil operating temperature

[Dozzer]

Personally as long as its got oil in it and its not got above around 115C it should be OK, as the ASTM D445 standard tests the viscosity of oils at 100C as part of operating range.
Most oils get lot thinner there, but that's what you want, or the gearbox is trying to stir treacle.
Oils will have an Upper service limit. but if you get there, you probably have other issues too, like a shagged box with knackered bearings anyway.

 

[voipio]

Just remember the red dot isn't necessarily where the temp sensor is "looking".

Measuring some bearings on a machine in Olympia, I was caught out by the dot being on the nice black bearing housing (good for decent temp measurement) but the actual sensor was telling me the temp of the mesh guard a foot in front of me.

The point and shoot infrared thermometers do not measure the temperature at the laser spot itself. Instead, they "see" an area that is defined by the distance to spot (D:S) ratio The D:S ratio indicates how large an area the thermometer is measuring relative to the distance from the target. For example, a D:S ratio of 12:1, which seems fairly typical, means the measurement is from a 1-inch diameter spot, when measured from 12 inches away,and its centre will be slightly offset from the.laser spot (since the laser aperture is to one side of the thermal sensor aperture). To get a reasonably accurate measure of the temperature of a piece of insulating tape stuck to a metallic surface, the thermometer needs to be placed with the thermal sensor aperture close to and directly over the tape, which means the laser spot will be off to the side of the area being measured.

Thermal imaging cameras are rather different, since the lens at the front of the camera forms an image on the thermal sensor array. Effectively, every pixel in the array provides a temperature value. To be able to read this out requires dedicated software to process the image data. Usually, the camera itself will only provide the user with a themperaure value of the centre pixel, or the centremost pixels.

 

[minimutly]

Personally as long as its got oil in it and its not got above around 115C it should be OK, as the ASTM D445 standard tests the viscosity of oils at 100C as part of operating range.
Most oils get lot thinner there, but that's what you want, or the gearbox is trying to stir treacle.
Oils will have an Upper service limit. but if you get there, you probably have other issues too, like a shagged box with knackered bearings anyway.

I would guess that avoiding a shagged 'box is the idea...
I'm in the " 70 degC " is about right for protecting the innards, anything over 85 and I would be looking for a cooler camp.
I don't have any data or hard evidence to back this up, just years of experience, so please don't have a go, it's just my opinion.

 

[Dozzer]

I would guess that avoiding a shagged 'box is the idea...
I'm in the " 70 degC " is about right for protecting the innards, anything over 85 and I would be looking for a cooler camp.
I don't have any data or hard evidence to back this up, just years of experience, so please don't have a go, it's just my opinion.

would think 70-85C is a good range, but the temp is just a function of the friction in the box, so if you have been beensing it down a motorway it will have heat soaked quite well and at a higher temp?
I was just answering the "whats the oils upper working temp" question.

 

[Smallfry]

That really isn't a problem. Couldn't put your hand on an R380 after a long drive either, even though some of them had a cooler fitted

 

[badabec]

Hello, I emailed Castrol:

thank you for contacting us!

We apprise you the Classic EP90 has excellent thermal stability.
The flash point is 282c which is very high. Operating at that temperature, it would also increase oxidation and degrade additives, but that would give a short term maximum limit of around 180c.

For further questions, we remain at your disposal/


Kind regards,
Castrol Technical Service

 

[Bornfree]

I've fitted temp sensors to the gearbox and transfer box on my ssangyong 4x4 the highest gearbox temp I've seen is 75°C and 68°C transfer box. But they both run ATF.