Outer Limits 4x4 Board

Hi Guys
Any idea what would make gearbox oil black?
Changed mine at the recommended 120,000 service and it looked more like engine oil.
Its an 03 Courier
Cheers

Dirt getting in the oil? Was it watery at all? Do you go offroad? Do you have gearbox breathers? Have you had it since new?

Has someone added any of the molly based oil treatments ?

Got a second hand transfer that was absolutely black internally, but was in good condition. Previous owner had use an oil treatment.

MightyMouse wrote:Has someone added any of the molly based oil treatments ?

Thats not a bad idea actually.

All the gearbox oils i've seen were either white, grey, very dark gold, or normal oily gold color. Never black - except one or two diffs.

Coxy

not watery at all, dont go off road much (unfortunately), has a breather, there was a fair amount of air pressure when fill plug released, could be blocked breather perhaps? too much heat?

There should be NO pressure at all inside the diff housing. Your breather will be blocked for sure. If you leave it, you'll be destined for a lifetime of replacing axle and pinion seals.

Coxy

coxy321 wrote:There should be NO pressure at all inside the diff housing. Your breather will be blocked for sure. If you leave it, you'll be destined for a lifetime of replacing axle and pinion seals.

Coxy

I think he is talking about his gearbox

Sorry guys!! Was thinking about my diff all day...

Still, what i said still goes.

Coxy

thanks for the advice, will take a look at the gearbox breather

Just change the oil and monitor it in 10,000k's.
With the breather(s), toss them away and run a hose into engine bay with a cheap small petrol filter on the end.

Bazzle

yeah i think i'll do that, thanks for the tip

I got my rebuilt gearbox back and the oil was black as could be. Had an additive that made the oil go like motor oil. Guy warned me as I left the store that the oil would be black as the ace of spades