Gearbox-Oil LT95

[Larosto]

Hello all there,

what oil do you drive in your LT95 gearbox? The manual says in old ones SAE90, and in newer ones engine oil 15W-40. How can I decide whether I have an old or a new one? Can the oilpump work with SAE90 or SAE 80W-90? Is there anybody who has tried it for a longer time?Would it make sense to drive different oil in main gearbox (15W-40) and transfergearbox (SAE80W-90)?
`hope to get some answers...

regards

Horst

[sebking]

My manual says 20/50 engine oil?

Been thinking the same question for a while too.

[sebking]

http://forums.lr4x4.com/index.php?showtopic=39425

http://www.landroverexchange.com/forum/ ... 19744.html

http://groups.google.com/group/alt.fan. ... 78b7b78efe

[map1275]

I would suggest you are not reading your reference source correctly. As per the previous posted link, the LT95 (the only gearbox found in the Stage One) uses engine oil in the gearbox and transfer case.

As per the old phrase: north-south oils and east-west oils. Everything that is north south is engine oil, all else is gear oil.

[firemanshort]

I mistakenly used 90W in my gearbox. It does ok unless it is cold outside. Then the shift from fisrt to second is miserble.

As soon as I can get to it, I will drain and replace with 50W motor oil.

[Rob]

My manual says engine oil in main and transfer gearbox. I used 15-40 oil in mine and it works ok

[stirlsilver]

This question has come up a few times now, I pulled this from http://stage1v8.org.uk/phpBB2/viewtopic.php?t=850

I use Castrol EPX 80W-90 in my gearbox no problem.

As I understood it the reason landrover specified engine oil back then was because there wasn't any good quality gearbox/diff oils around then. It is completely different today so it is suggested to use gearbox oils now.

But it seems that either option works just fine

90W is too thick for cold temparetures. I have that in mine and I can not shift the truck without effort and grinding unitl I get it warmed up.

EP90 and EPX 80W-90 are completely different. The EP 90 is the thick nasty smelling oil used in diffs and transfer boxes and series main boxes pre 2000ish.

You are right it's not suitable for Stage one main boxes as it's too thick for the oil pump to deal with.

EPX 80W-90 is a new high shear low viscosity gear oil which feels and runs more like engine oil. It's now used in axles and transfer boxes of post 2000 discovery etc. Unlike engine oil used in gearboxes it survives the bashing shearing and abuse the gears give it. It stays cleaner and holds it's original structure longer.

The only drawback is it's not cheap.

The disco 2 uses EPX 80W-90 as standard and the car has one of the quietest transmissions for a 4x4.

[Larosto]

Hello all together,

first I thank you all for the answers. I researched some hours about this theme, and now I can tell you, Stirling and Dave are completly right. Many people in the scene say that 80W-90 is too thick, but it is not so. The viscosity of 80W-90 is nearly the same as that of 20w-50. I drew the curve of the viscosity in dependence of the temperature of each oil into a temperature-viscosity chart, and I saw that it was nearly the same. Another important aspect is, that the oil doesn`t attack copper and copper-alloy or brass. This you have to clear with your supplyer. Castrol EPX 80W-90 achieves these aspects, so I think one can use it for the gearbox.
I will do so, because the gearbox seems quiter and smoother to me using this oil. It also seems plausible to me, that there haven`t been gearboxoils which can be used in Summer and in winter too, at the time the gearbox was developed, so the engineers decided to use 20W-50 in these boxes to avoid a change of the gesrboxoil in summer and winter.
I think, if one uses to run LT95 gearbox with 20W-50 engine oil, you have to change it in short intervals, because it gets rather thin during a short time. 80W-90 keeps cleaner and viscoser when it is used in a gearbox.
I will take an oil sample after driving about 1500 miles, then I will tell xou my impression

kind regards

Horst

[stirlsilver]

From something I have just discovered.

DO NOT USE EP or EPX oils in the gearbox or transfer case, this oil contains suphur and phosphorus and can corrode yellow metals (which the LT95 has) under high temperatures. If you are going to use a gearbox oil make sure it specifically says it doesn't contain these compounds!