Gearbox Oil

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Originally Posted by gromit

Doesn't it thin to the 75W ?

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No.

Oil gets thinner as it heats up, thicker as it cools. The aim of the manufacturer is to make it STAY thicker when it's hot, and stay thinner when cold.

So the 100C viscosity is much less than the 40C, and waaayy less than at 0C. That's why we drain the oil when it's hot, it's thinner!

The W rating is based on the temperature at which the oils thickens to a set viscosity. If it gets that thick at -12C, it is rated 85W, if at -26C it is 80W etc.

So the blender is attempting to stop the oil getting too thick at low temperatures, whilst also stopping it from getting too "runny" at high temperatures. There are three ways to achieve this:

1/ Use a synthetic oil which has a more stable viscosity profile

2/ Add viscosity modifiers that react to temperature increases

3/ Blend various mineral oils, thicker and thinner ones, to achieve a mix that stays in spec.

Synthetic oil is expensive, but most 75W/xx are synthetic simply because it's too hard to make mineral oil behave this way. Viscosity modifiers are also expensive, and may impact other aspects of gear oil performance. Option 3/, blending mineral oils to suit, allows the manufacturer to cheaply meet the 80W or 85W specification. However as a side effect of keeping the oil thin enough at low temperatures, it is often (as seen in the specs I quoted previously) also at the low end of the SAE90 high temperature viscosity. The SAE90 specification is a range, and it's easier to hit the lower end of the range - the customer, after all, is never expected to investigate any further than the shiny packaging! A straight EP90, because the low temperature viscosity is not specified, can be more easily made to stay at the high end of the SAE90 specification.

MILD EP GEAR OIL SAE 110

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Originally Posted by whitehillbilly64

MILD EP GEAR OIL SAE 110

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Yep, that's what Global Roamer recommended for Roamerdrive equipped gearboxes in Australia. My local Auto One can get it on special order (about $16/litre), and Motofluid.com sell it for $12.50 but the delivery cost is about $25 for a box of 6 x 1L so it also ends up about $16/L but would be dirt cheap if you could pick it up (Bayswater Vic., if they allow pick-up!).

I picked mine up from Auto One this morning....

Starts to get expensive if you use a 'big brand name'.
I'm using a 75W/90 GL4 direct from a blender for about $24 for 5 litres (haven't purchased any for a while). Problem is you have to collect in Bayswater.
I looked into getting it Interstate for someone and because they sell through agents the price wasn't so attractive.

Penrite are in Wantirna South but I don't think they sell direct.


Colin

When I installed the Roamerdrive in my vehicle I chased around for a GL4 75W-90 and came up with Mobil XHP 75W-90. I had to buy a 20 litre drum as that was the smallest it came in. I think it was around the $160 mark. Also, from memory Roamerdrive recommended an oil change after a thousand or so kays. The other brand synthetics I found worked out pretty expensive per litre, especially if your going to tip them out after a thousand kays.


Cheers Mick.

By the time you add some freight costs and a reseller's mark-up (anywhere from 30% to 100%) you might find that the $24.50 has caught up with the Penrite price!

On the other hand, and I've never dealt directly with a blender so I don't know what their minimum batch sizes are, if you could get them to blend a straight old-fashioned EP90 and use the "AULRO Courier Service" to distribute it to strategic pick-up points, you might create an attractive group buy!! Oil isn't limited by a short shelf life, and Land Rovers use a fair amount of EP90 (more if they're leaky!) so you might find people would be happy to buy it.

Put me down for 20L of "GromitOil EP90"!!

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Dear GromitOil,

As a classic car owner, I am very interested in your GromitOil EP90 Classic Gearbox oil. Those of us who drive such vehicles often struggle to decide which if any of the modern products will be suitable for our older cars, especially as many experts and even the oil companies themselves give contradictory information regarding the suitability of their products. It is refreshing to once again be able to purchase "the product I want", rather than being forced to buy "the product they want to sell".

Having finally sorted out my gearbox oil conundrum, could I ask if GromitOil has any plans to expand it's classic car range? I would be very interested in a good, old fashioned anti-freeze product along the lines of BlueCol or Duckhams Universal, as originally recommended for my vehicle.

Thanks in advance,

Warb

======================== ;)

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Originally Posted by mick88

When I installed the Roamerdrive in my vehicle I chased around for a GL4 75W-90 and came up with Mobil XHP 75W-90.

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I had the same issue, so I contacted Ray at Roamerdrive about my 86" and received the following reply:

"I don't like synthetics in Series in hot climates - tends to weep out and is a bit thin so makes things noisy.. Australian Penrite has what they call a "Mild EP" GL4 gear oil that they suggest in the transfer case of Series Is and I think this will be very good."

So on his recommendation I've picked Mild EP.

To add some background that might explain my current fixation with gearbox oil, yesterday I spent $4K on a new gearbox (trade price, retail is >$5K) to go in a 170,000km 5 year old Prado 150 because the synchromesh had failed. The vehicle was regularly serviced by a local garage who (obviously) don't use genuine Toyota oils. Did they use the wrong oil? Did that cause the problem? Who knows, but in future I'll be making 100% certain that the right product is used!

Regarding markups etc. I agree, that's why I buy direct. Huge saving and by dealing with a blender I'm not paying a marketing & sponsorship levy.

I'll ask next week if they will supply EP90 GL4 and minimum batch size but I haven't got the time to collect, distribute etc.


Colin

Quote:

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Originally Posted by gromit

I'll ask next week if they will supply EP90 GL4 and minimum batch size but I haven't got the time to collect, distribute etc.

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If you talk to them, and if they are at all open to the idea and the batch size and price is sensible, remember our concern is the high temperature viscosity. We are looking to be right at the very top of SAE90, or ideally slightly above. The EP90 "label" is to make people comfortable that they are using the right product, but from a technical standpoint we know that Penrite already recommend Mild EP, which is right at the top of SAE110, so anything from the very top of SAE90 to mid SAE110 range would be ideal.

If it can be done at a good price, we could put it in the Group Buys forum and see if anyone is interested. If there is enough interest I'm sure the logistics of distribution can be sorted!

Spoke today to a local, restorer, Mechanic,and he swears by this stuff.
Runs it in modern or old machinery.
His modern motorbikes run 5oc cooler, and the older stuff runs quieter.
Cuts back on friction, and recons the Fairly Overdrive, which he is familiar with, would run quieter and smoother, with it in.
Any one used it.
Can be used anywhere.
Just had a quick look online, and its not liked

Lucas Engine Oil Stabilizer - 1 Litre - Supercheap Auto Australia

whitehillbilly