TD5 Differentials Synthetic oil

[Desert Cat]

Hi Guys,

While Land Rover differential stock lubricant says:

"Multigear Texaco 75W90R" semi synt into the diff's

Is it better to go with:

Mobil 1 Synthetic Gear Lubricant LS 75W-90

Or it can harm any metals inside the diff due to oil additives?

[BogMonster]

The Td5 diff is essentially exactly the same as any other Land Rover 24 spline 2 pin diff as fitted to most Defender 90s in the last 15 years, the front of Defender 110s, and Discovery 1 vehicles. So any decent EP gear oil will do - I use Castrol EPX80w90 in mine. Not sure where the synthetic requirement came from - it's nothing fancy just an old tech pig-iron diff.

[Desert Cat]

Yours is: Castrol EPX 80W/90W

and it's mineral, not semi synt of full synt.

Since diif's are noisy could the full synth reduce the noise & wear/tear

[Desert Cat]

Since it's "old" it hammms and noisy.

The oil you are using is the Castrol EPX 80W/90

which is mineral oil, no semi-synth or full-synth.

does the use of full-synth can harm the diff's metallic parts, some where I read about some chemical reaction...

[JimAttrill]

What you have doubtless heard about is the fact that GL5 gear oils have ingredients that will attack bronze components. These components are normally synchro rings which are of brass or bronze. The differentials and transfer boxes fitted to all LR vehicles have no brass or bronze components so it is perfectly safe, in fact preferable to use GL5 rather than GL4 oils in them. If you can afford fully synthetic GL5 EP90 oils so much the better.

Redline oils are very good..... but expensive