oil choice lt 85 gaerbox

[jasper110]

what would be the ideal oil to put into te above gearbox?, mine has a pronounced whine, any cures? also when i removed the gearlever gaiter and soundproofing(ha ha!)pad i noticed a filler plug on top of the box behind the hi-lo lever and next to the breather, should i use this and fill her to the top?

any comments helpful,

cheers.

[LRCounty]

Don't fill it to the top. There is a fill plug on the left side of the gearbox...use that. Fill until oil starts coming out.

I had an LT 85 in my previous 110. I had a nice whine too. I tried straight ATF, then a mix of ATF and Moreys heavy duty oil stabiliser. Finally I tried Redline MTF, and that seemed to help the whine the most. After a while with Redline, I drained a small amount out and threw in some ROIL (worst it could do was nothing) and this improved it a lot more.

Cheers
Andre

[Maggot4x4]

The manual reccomends motor oil but Motor oil is not good enough for the pressures between the gear teeth. The rover boxes need a low viscosity GL4 gear oil (high viscosity will give other problems).

Land Rover now recommends MTF-94, which is produced by Caltex.

I use Castrol Syntrans 75W85, which is fully synthetic.

Other suitable manual transmission fluids are:

Castrol VMX 80 (some people like this and others don't) or SMX 80
Redline MTL 70W80
Shell Spirax GSX 75W80
Valvoline Duragear 70W85
Penrite Manual Gear Oil Xtra Light

[LRCounty]

Oops...sorry for the mis-info. Redline MTL it was!!

[maggsie]

Maggot wrote (Land Rover now recommends MTF-94, which is produced by Caltex.)
Can you tell me where you found this info for the LT 85 Gearbox. I ask the question as I currently have mine in pieces to replace the mainshaft. All the gears are in excellent condition (230000klms) and I have been using Visco 2000 since I bought the car (over 2 years).
Regards
Maggsie

[shaunp]

Penrite make a classic gear box oil to use in place of SAE30 mineral engine oil in MGs, Jags Austin healys etc, it is called GEARBOX OIL 30 and is part of their histroic range. Works good in MGs and jag Moss box. You need to be carefull running extreme presure oils in boxes in old boxes that may have yellow metal in them as trusts and bushes ar it can eat then. GL4 is probably ok in old boxes as it is a mild EP.

[JDNSW]

The problem with using higher viscocity gear oils in these gear boxes is that the oil pumps are likely to fail in cold conditions - not a serious problem for much of Australia, but sooner or later it may happen. If it does there is no indication - until other bits fail under load maybe tens of thousands of kilometres later.

The load on gear teeth is low compared to differentials for example, and almost any lubricant is adequate from this point of view, same for bearings. At high loads, particularly in hot conditions the cooling properties of the lubricant become important, hence the oil pump, but the difference in this between oils is very little - just a matter of circulating the oil around.

Where the oil becomes more critical is in the performance of the synchromesh and gear shifting in general. This depends on the slipperiness and adhesion properties of the oil, and quite small changes can greatly affect the feel of the gearbox, hence the variety of recommendations as the manufacturers try to get the best all round performance. But we are not talking about failure of gears or bearings. Most gear and shaft failures, and probably some bearing failures result from shock loading of the drive train due to extreme conditions, lousy driving, or both. (excluding design problems that prevent adequate lubrication!)