The GMC CCKW

Does anybody have any views on using Hypoid gear oil in a non hypoid [but bevel]gear application? Any comments welcomed.

Karoshi

Todays # EP 90 gear oils in the US are suitable for all axles including Hypoid, and have been since the late 40s.
Joel

Joel thanks. In the specific application of the split axle i'm wondering if GL4 might be more appropriate than a GL5 oil. I can not seem to get a consensus. The question of the sulfer content has been mentioned by various suppliers. Any thoughts.

Karoshi

Hi Karoshi,

Sulpher content in some hypoid oils will attack the bronze bushes in gmc winches, you should use the correct type and grade of oil in them.

GL 5 grade oil is suitable for use were a GL 4 may be used, as the GL 5 exceeds the requirements of GL 4.

Extreme pressure (EP) oil may be used in differentials or gearboxes, hypoid oil should always be used in differentials requiring it,
however it would not matter to much if used in a non hypoid gear application. Do not use the other way round i.e. non hypoid oil in a EP application.

I hope this makes sense.

cheers,

Brent Delaney.

Apparantly in some areas of the world the Oil technology is different, the gear oils here are Multipurpose and suitable for Hypoid. The only caution I suggest is not to Buy the Discount store brands(Sams Club) that sell for $19.95 per 35 #(5 Gal) Pail, it is garbage. I am using Mobil at present, but will be going to Kendall next purchase around $55.00 for 35# Pail. If you want to see what happens to gears with sub standard oil, attend some 1/4 Mile drag strips, and tou will see gears that spall (chip and pit) with cheap oil as it will not take the pressure.
Joel

Brent thanks, it was the sulphur attack that concerned me. The 'rough' rule of thumb that seems to immerge from UK enquiries is; pre or post 1960.

EP gear oil before, Hypoid rated after.

And from Joel,... good advice as ever; no I don't use cheap branded oils. I've been a student, been there done that,and...paid the price.

Karoshi