Thread: Gear Oil etc

Originally Posted by whitehillbilly64

Hi Dark,
I got this from Repco.
$12 per ltr.

https://www.penriteoil.com.au/produc...id_products=80

whitehillbilly

Nice. Couldn't find that when I was looking. Will give it a try when I've used up the other stuff.
Thanks

C00P

The problem with GL-5 is that the EP additives can cause corrosion of the yellow metal parts in the gearbox. Unfortunately, from my understanding, the issue is not as simple as GL-4 vs GL-5, as the problem is not the EP rating of the oil, but the actual additives used by the manufacturer. Unfortunately, what is actually used in the oil is not exactly headlined by the oil manufacturer, and may even change between batches. And corrosion or not of yellow metal is not part of the GL specification.

There is no guarantee that simply specifying GL-4 removes the problem, and no certainty that GL-5 means there is a problem.

I have used Castrol GL-5 products for years without issues - but then I have not had the gearbox apart either (no reason to!). Further, I suspect that corrosion issues will only exist when the oil in use contains significant amounts of water. This suggests that it would be a good idea to change the oil in the box fairly often (annual?) if you live in a humid climate especially if the vehicle has little use. Less of an issue if you live inland and use it regularly enough to get the box hot for at least half an hour every few months.

John

I use this.
I think it was around $100.00 for 20 litres.

Originally Posted by incisor

Have anyone actually seen gl5 oil cause a problem and I not interested in heresay.... Has anyone here actually seen it cause an issue?

Because I have been using gl5 for a long time now and am yet to see an issue.... Touch wood...

I haven't 'seen' problems but don't do enough Km's and have mostly vehicles with already very worn gearboxes.

There have been reported problems but the blender I buy my oil from told me their GL5 'should' be OK but then organised some GL4 to be blended for me.

Problem appears to be that the 'high pressure' additive in GL5 can attack yellow metals (synchro & any bushes) and cause synchro's to not work as well as with GL4.


Gears Lubrication , Oil API Specification Review - Engineers Edge
https://www.linkedin.com/pulse/diffe...ion-daniel-shi
Guidelines for Using Gear Oil in Specific Applications

The oil I get costs about $25 for 5 litres and is GL4 so I'll stick with that but understand that some people are finding difficulty sourcing GL4.


Colin

I sent Penrite an enquiry as to what they recommended and got this back:


A GL-4 oil has a little less EP or extreme pressure additive in the formulation. We don't do a GL4 as such but I believe our Trans Gear 75W-90 should suit. GL4 oils may have been requested for, to be more compatible with copper alloys but our formulations are friendlier with copper alloys than what oils, back in the day, were.
For your gearbox Gear Oil 80W-90 (but Trans Gear 75W-90 is ok).

Transfer case> As for gearbox, both options, 2.5L

Front diff> ONLY ProGear 75W-85*, 1.7L
Front axle swivel pin housings, use ProGear 75W-85, 0.5 litre each.

Rear diff> ONLY ProGear 75W-85*

*Product code for 2.5L is PROG75850025 (rated GL-4+). Note that this is normally considered only for gearboxes, but is right for your model.


cheers,
D

Penrite's website is pretty comprehensive and if you drive a pre-1970 vehicle this is their specific recommendation...

Penrite Pre-1970 - NetLube

Cheers,

Lou