Lube For Hypoid Gear Box?

[madman]

Well im well on the way to completing a Hypoid Gear set. Its been stressful. For a customer who if he doesnt get this Machine going all his employees will be out of work, as the Line depends on this Machine Operating. Anyhow will try later to get pics out somehow. My question is what would you use inside the gearbox for Lubricant? It (Gearbox) turns slowly. It Does get high Pressures though. Thankyou as always MMike

[jdunmyer]

Mike,
If there's no manufacturer's instructions, I'd use something like 85w-140 synthetic gear oil, as used in truck differentials. That's a pretty similar application.

Note the "synthetic", that's what's specified for the Dana axle in my Dodge p/u.

[Willy]

First thing that comes to mind would be hypoid gear oil.
The siding gear interfaces would be protected from wear due to the additive package present in rear axle differential lube.

Two things to keep in mind are the operating temps encountered by the gearbox, as far as viscosity choice goes, and are there any brass or bronze components present in the gearbox. Due to the EP additives present in most hypoid oils they are usually not recommended because of the corrosive nature of these additives to brass or bronze alloys.

[darryl]

I would have said hypoid gear oil as well. I was not aware of the corrosive nature of ep additives on brass or bronze- maybe that's something you can read on the side of the can- safe for- etc.

[Arcane]

Texas Refinery Corporation's "790 SURE® UNIVERSAL
GEAR LUBRICANT" is good stuff.
Timken OK Load is 70 lbs for their 80W/90 and 75 lbs for their 85W/140.

[knudsen]

Isn't the corrosion thing from the far past? Isn't anything from the autoparts safe for manual transmissions? I think it's all GL 4 or 5 and safe for brass?

[Willy]

Isn't the corrosion thing from the far past? Isn't anything from the autoparts safe for manual transmissions? I think it's all GL 4 or 5 and safe for brass?

No the issue still exists. It is all very much dependent on the additive package in the oil.
Unless a product specifically states that it is safe for use in gearboxes containing yellow metals assume that it is not.
That's one of the major problems with oil, unlike other components, it always fits.
A lot of lubricated components suffer a shorter life because of mis-application of lubes. One very important reason to always follow the OEM's lube recommendations, unless a lubricant supplier specifically states that their product meets or exceeds those of the OEM.

Here are a couple of links explaining the complexities of gear oil applications and what the additives package peculiarities are under the different criteria of gearbox design and end use.

From a book by Robert Bowen:
How to Rebuild and Modify Your Manual Transmission

And a Wikipedia link about ep additives.