Thread: OILS AIN'T OILS - R380

Originally Posted by DEFENDERZOOK

is that one too many zeros there........or is your rover a taxi.....?

Well spotted Zook ! and your prize for spotting the deliberate error is



just the satisfaction knowing you have good observation and comprehension skills

Thanks Rick for the answers. I understand here that Motul Gear 300 75W90 fully synthetic should be better of MTF94 in R380 shift.

I use Motylgear 75W90 Technosynthese (semi-synthetic) for the two differentials and the transfer box and MTF94 for the R380.

For the next service I could consider putting Motul Gear 300 75W90 in R380: from what I've read is not worth it to use the 75W140 also because temperatures are not Saharian.

Should I consider using Motul Gear 300 75W90 for differentials and transfer box also or can I keep Motylgear 75W90?

MTF94 may shift a little easier at sub zero temps than Gear 300 as it also has a high VI and is only a 75W-80, but in my experience shears reasonably quickly.
It is a very good manual gearbox oil, regardless.

It just depends if you live up north in the Alps or down south where it's hotter

I'd stick with the Motylgear in the t/case and diffs.

I tell you what I know...
In my humble experience, all specialist mechanics that deal with Defenders has always said that in the R380 you can only put MTF94 because it has be forulated specially...

Even though I always thought it was strange and exaggerated I always put MTF94

They say that without MTF94 I can have jamming and synchros wear faster. As limit, in case of problems with MTF94 you can put ATF Dexron III.

MTF94 isn't anything 'special', it's just a good, 75W-80 Manual Transmission Fluid of which there are any number these days from all the blenders.

Manual Transmission fluids differ from diff oils and engine oils in that they have the 'correct' friction modifiers for good synchro action, unlike an ATF, engine oil or differential fluid (which shouldn't be used in a manual gearbox)

What these friction modifiers do is that their coefficient of friction increases with reduced speed differential of the sycnhro clutches.
This allows the synchro faces to 'bite' properly and slow down even more, matching speeds and allowing the clutch dogs to engage smoothly without clashing.
Engine oils in particular tend to work the opposite, where their coefficient of friction decreases with reduced speed differential.
ATFs vary.

MTF's do vary in the speed of action from brand to brand, blend to blend.

What works best in one make doesn't always shift brilliantly in another, and as one of our resident full time Land Rover mechanics has said, even R380's can vary in their preference.
Texaco did blend MTF94 for Land Rover to replace ATF, so you could say it's optimised for their use, but that doesn't mean something else doesn't work as well or better.

I started using Castrol Syntrans 75W-85 in 2002, I had too much gear rattle at high ambient with MTF94 and knowing it's only a semi-synthetic I started to experiment to find something with a longer life.
A few years down the track I tried Redline MTL and then a mix of Redline MTL and MT90 for about 15,000km then back to Syntrans and it's only the last four years I switched to other fluids, eg Gear 300.
It didn't help that we could only buy MTF94 from a Land Rover dealer, if they'd sell it to us, or from a Caltex (Texaco) distributor only in 20l drums.
I'd found Syntrans to perform better than MTF94 anyway, and everyone that I suggested it to seemed to agree.
I also remember suggesting it to a Castrol Australia tech too as at that stage they only recommended ATF.

Caltex then stopped importing the oil when Land Rover started dealing with Castrol.

My gearbox has over 300,000km on it and the synchros are still fine.
Synchro action and speed of engagement varies between the different blends, but the gearbox is fine.

My 'box doesn't have an oil cooler, and in high summer temps and under high load the gear rattle was unacceptable for me and the synchro engagement deteriorated, even with Syntrans.
As I mentioned above, the life of Syntrans in one of these boxes is only 20,000km, yet it's fine for up to 400,000km in heavy trucks.
IME, the R380 is a fluid killer. Too small a volume of fluid, a cast iron case, limited oil cooling along with dealing with an oil pump and spiral cut gears shears the oil.

To try and help this in the short term I tried Torco RTF and have found that so far, Gear 300 gives me the results I'm after, but someone else may feel differently.
Most here are extremely happy with Castrol Syntrans 75W-85, some prefer and use Redline MTL, some Valvoline Duragear 75w-85, etc.

All are better than an ATF for long term durability IMO.

I am very grateful for the very exhaustive answer.

The Syntrax 75W-85 oil you're talking about where I live is called Castrol Syntrax UNIVERSAL PLUS 75W90 fully synthetic that meets API GL-4 / API GL-5 / API MT-1 and says it is approved for replacement intervals 300,000 km in synchronized manual gearboxes.

Originally Posted by rick130

Manual Transmission fluids differ from diff oils and engine oils in that they have the 'correct' friction modifiers for good synchro action, unlike an ATF, engine oil or differential fluid (which shouldn't be used in a manual gearbox)

Generally, gearbox oils, transfer box oil and differentials oil are all in the same category, for example, if I go on the Castrol site it suggests to me the same oil (Castrol Syntrax 75W UNIVERSAL PLUS 75W90 ) for gearbox, transfer box and differential. How can I distinguish a gearbox oil from a transfer box or differential one?

What do you think about of this?
Mobil™ | Heavy Duty Engine Oils | Manual and Automatic Transmission | Mobilube 1 SHC™ 75W-90

Is it ok for the gearbox? It seems to have similar characteristics to Castrol and Motul ones ... I can use it for the transfer box and differential?

What do you use?

Thanks

Originally Posted by bismillah

The Syntrax 75W-85 oil you're talking about

Syntrans oil is different to Syntrax. Syntrans is what most use here as the standard replacement for MTF 94.

Garry

Originally Posted by bismillah

I am very grateful for the very exhaustive answer.

The Syntrax 75W-85 oil you're talking about where I live is called Castrol Syntrax UNIVERSAL PLUS 75W90 fully synthetic that meets API GL-4 / API GL-5 / API MT-1 and says it is approved for replacement intervals 300,000 km in synchronized manual gearboxes.

[snip]

What do you use?

Thanks

No no no.

Syntrans 75W-85.

Syntrans comes in a few flavours, Syntrans Max 75W-80 for ZF commercial transmissions, Syntrans B 75W-80 is an Australian version for Ford high performance cars here, Syntrans M 75W-90 for Road Ranger and Spicer HD truck transmissions.

Syntrans Universal 75W-85 is the oldest version and the one most suitable fro the R380 in Australia, Africa and Southern Europe, eg. Spain, Portugal, Southern Italy, etc. It also has a Volvo HD Truck part number.


European Syntrax Long Life is another oil altogether, and is formulated for transaxle use.
It has only recently been re-named Syntrax in Europe, (the original name escapes me ATM) while carrying that name in Australia for many, many years.

AFAIK (and I could be wrong) I believe all these various Castrol brews were developed by Castrol Germany.