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Gearbox Oil
Posted: Mon Oct 10, 2016 1:18 pm
by mbellinger
I am carrying out a conversion to overdrive on my 1300. I will be using an overdrive box from a 1500 Spitfire.
What is the recommended oil for these 'boxes and do any other members have any particular recommendations regarding brand, etc?
All suggestions gratefully received.
Re: Gearbox Oil
Posted: Mon Oct 10, 2016 1:48 pm
by cliftyhanger
EP90 gl4 is the recommended stuff.
I have been using comma ep 80/90 gl4 for about 20 years in all my cars gearboxes and diffs, no complaints. There may be "better" but this stuff has never been an issue. In all honesty, any gl4 gear oil will be good. Indeed, I have wondered about using comma synthetic SX 75/90 GL4 oil (as used in type 9's etc) but it is harder to find than std gear oil.
I think the GL4 bit is important, as the gearboxes have yellow metals in them. If modern GL5 oils actually attcak yellow metals is also open to debate, but to be safe use GL4.
Re: Gearbox Oil
Posted: Mon Oct 10, 2016 6:17 pm
by MIG Wielder
I have used Penrite T90 Transoil for some time now and it works well in my 1850 O/D gearbox.
I get it from the various Restoration Shows
http://www.holden.co.uk/displayproduct. ... de=015.971
HTH,
Tony.
Re: Gearbox Oil
Posted: Mon Oct 10, 2016 7:47 pm
by Jon Tilson
I use Castrol 80W90 which comes branded for gearboxes and axles in different bottles.
There used to be an issue with the EP additive leaching the carbon from sintered bonze bits like synchro cones
I suppose but the overdrive and bearings have very little sintered in them.
It would be a serious problem on early Sprint boxes with sintered gear bushes on the main shaft.
I believe the issue was solved a while ago with a new formula for EP additive so its no longer an issue.
Jonners
Re: Gearbox Oil
Posted: Mon Oct 10, 2016 7:49 pm
by Mahesh
I always thought the overdrive boxes required an EP oil.
Re: Gearbox Oil
Posted: Tue Oct 11, 2016 8:56 am
by Jon Tilson
No they don't.
EP is designed for the rolling and sliding action of the bevel gears in diffs.
MGB's and a few other cars with overdrive just run on engine oil in the box.
Jonners
Re: Gearbox Oil
Posted: Tue Oct 11, 2016 10:54 am
by cliftyhanger
IIRC laycock spec a non-ep oil for their overdrives. But Triumph spec ep for the gearboxes with or without overdrive.
Up to you, but I am sticking with the manufacturers recommendation! Likewise, I doubt there is any advantage of GL5 oil over GL4, so why take the risk?
Anybody know for certain if all GL5 oils are yellow-metal safe? I know some are, but couldn't name them.