I know we discussed the difference between GL-4 and GL-5 specs here, viewtopic.php?f=7&t=1441&hilit=gearbox+oil
But how important do we think it is? There're no decent motor factors near here, all the local sources have only got the GL-5, and I can't decide whether it's worth going further afield to hunt for GL-4.

Joolz,
since it's a newly fitted gearbox, you'd probably be changing the oil after its first good run out anyway, wouldn't you?

For the short time that the GL5 would be in the 'box, I doubt that those 'yellow metal eating' molecules will have time to do much harm.

ken

( Fwiw, I used a semi-synthetic GL5 oil in the old Dyane's gearbox for about 6 or 7 years, then switched back to Total GL4 when I bought a big drum of that stuff.
The gearbox still works as good as it did when it was installed 13 years ago. )

Thanks Ken,
I sure it isn't too important, but I don't like doing something I know should be done differently.

I wasn't aware I'd be changing the oil again so soon, I did clean all the sludge out of the bottom when I had the bell housing off. Would that be the reason?

Because if there's sludge in the bell housing, what's lurking in the rest of the casing?

Gearbox oil changes seem to be more neglected than engines oil changes, judging by the black gunge which often trickles out of some when they're drained.

At less than a fiver, to treat the first fill after being recommissioned as a 'gearbox flush', it always seems worthwhile to me...

ken

I was quite thorough, I got my toothbrush right back under the diff as far as I could see, and then gave it a little rinse with some heating oil. I'll see how I feel in a few hundred miles time, if the box is a good'un perhaps I'll treat it.

how regularly should an old box be changed? i havent changed the oil since ive had mine, so the oil in there could be years old,
when i serviced we looked at the box oil, it looked very clean, but this was at the level bolt, where is the drain (asssuming the sludge would sink to the bottom whilst the good stuff would be on top?

I'd say change it now anyway so you know exactly how old it is.

Esp. as you seem to like tinkering, it's another "new" job tickd off the list.

t'was my plan, did that with the engine, serviced it so i knew where i stood

is the drain plug on the bottom?

Drop the gear box oil at the same time as engine oil, easy and cheap.
Gearboxes are now minimum 20+ years old and they are breaking down left right center. My advice is not to use any oil with GL5, only use GL4 making sure that the sulphate is none active (not eating yellow metal ( synchronmess rings)

It is in the Northern hemisphere, not sure if they have problems with that in the Southern hemisphere...