[coops]

Cheers Chris,
so the 75W90 semi synth is ok for the main gearbox? what is the GL4 and GL5 mean?
as what I have is SX75W90 GL5

 

[wozizname]

Cheers Chris,
so the 75W90 semi synth is ok for the main gearbox? what is the GL4 and GL5 mean?
as what I have is SX75W90 GL5

:+1 with Chris as fully synthetic is the way forward (no pun intended)
GL4 and GL5 is the oils 'make-up' and GL4 is what you need for your transmission as the GL5 will attack the syncro's.
Using fully synthetic removes all the problems with an oils 'make-up'.
I got mine from here as it was the cheapest I could find http://www.smithandallan.com/prodpage.aspx?id=1849
My truck and hannah77's are running it with no problems.

 

[chris vince]

If it is straight GL-5 do not use it in the gearbox it will have additives that could corrode the yellow metals in the baulk rings etc and in time wreck it, the gearbox needs GL-4 additives, as per Woz's earlier post.
As I mentioned before, IMHO take it back and get FULLY synthetic gear oil, it may say it is GL1-5 (all manufacturers have different literature), if it says GL1-5 and is FULLY synthetic do not worry about the GL-5 grading, as in fully synthetic the damaging additive sulphur is not used and a synthetic replacement is provided to give the extreme pressure properties.
So by using F/S GL1-5 oil you get the best of all worlds, extreme pressure protection (useful if towing) without the corrosive chemicals and nice easy slick gear changes even on the very coldest mornings.
Hope this makes sense?

 

[coops]

Just spoke to the motor factors.
they are ordering in for me some 75W90 FULLY SYNTHETIC oil for the gearbox and transfer box,
will be here Tuesday,

 

[chris vince]

Best way to go Tony.

 

[Jason the Hut]

effects of towing

So synth is the stuff when towing, my d22 gearbox got very hot when towing, i could even feel the heat on the gearshifter,
it was also smelling a little too.
no idea when any oils where changed, so i think a full change must be on the cards