The Ford Barn

COE Dan · 07-05-2015, 07:03 PM

Ford Barners,

I had to replace my rear axle oil on my '47 COE with the 2-speed axle after my brake job. All the Ford literature on the 2-speed axle directs the use of 90W EP oil if below 100 degrees and 140W EP oil above 100 degrees. I'm going with 90W based on my planned operating temperatures.

I've attempted to educate myself on this but have found nothing definitive for early Fords through a search of FordBarn or other online sources Some folks say GL-1 spec oil was what was available in the '30s/'40s but others say this is straight mineral oil with no EP additives. Others say GL-4 is usually ok but contains the same additives as GL-5 which apparently has a higher concentration that will eat away at "yellow" metal (bronze/brass) due to high sulfur content.

Here in Illinois, I bought a jug of Ford EP-90 Trans/Hydraulic Fluid from Rural King but I can't find a spec sheet online and they don't even list the product on their website. So, I haven't put anything in the axle yet.

Anyone have good information on what to use and what to absolutely avoid?

Thanks,

Dan

JSeery · 07-05-2015, 07:14 PM

Yellow metal should not be a concern in the rear axle. Different story with transmissions. I would use GL-4 anyway if it were me. GL-4 and GL-5 do contain the same type of additives, but GL-5 contains a lot more.

Drbrown · 07-05-2015, 11:26 PM

I use StayLub GL-4 90 or 140 .... ordered/purchased at my local NAPA store in Qt or Gallon containers. Some differential assemblies normally get hot during use and 140 may be preferred. Some use 140 if limited seepage is a problem. 140 is recommended for BW overdrives.

Ross F-1 · 07-06-2015, 09:42 AM

Many GL-5 EP gear oils have converted to additives that do not attack yellow metal. Walmart sells an 85w140 that says it is safe for use in axles and manual transmissions with copper-alloy parts.

COE Dan · 07-06-2015, 07:30 PM

Thanks for the info.

Dan

JSeery · 07-06-2015, 07:38 PM

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I missed the 2-speed part when I first read your post. Not sure if they require anything different that a normal rear axle. Maybe someone can comment?

Edit: Per Rotorwrench 4-07-2015:

"Rear axle can use any straight grade SAE 90 or SAE 140 GL-4 or GL-5 lubricant. They can also use any multi-viscosity lube. The transmissions use GL-4. SAE 90 in cooler climates and SAE 140 in warmer climates. Sta-lube GL-4 can be purchased from a local NAPA dealer in straight grades. You can also use it in the Columbia 2-speed axle."

07-05-2015, 07:03 PM	#1
COE Dan Senior Member Join Date: May 2010 Location: Now in Wichita, KS Posts: 251	What type of rear axle oil do I use? Ford Barners, I had to replace my rear axle oil on my '47 COE with the 2-speed axle after my brake job. All the Ford literature on the 2-speed axle directs the use of 90W EP oil if below 100 degrees and 140W EP oil above 100 degrees. I'm going with 90W based on my planned operating temperatures. I've attempted to educate myself on this but have found nothing definitive for early Fords through a search of FordBarn or other online sources Some folks say GL-1 spec oil was what was available in the '30s/'40s but others say this is straight mineral oil with no EP additives. Others say GL-4 is usually ok but contains the same additives as GL-5 which apparently has a higher concentration that will eat away at "yellow" metal (bronze/brass) due to high sulfur content. Here in Illinois, I bought a jug of Ford EP-90 Trans/Hydraulic Fluid from Rural King but I can't find a spec sheet online and they don't even list the product on their website. So, I haven't put anything in the axle yet. Anyone have good information on what to use and what to absolutely avoid? Thanks, Dan

07-05-2015, 07:14 PM	#2
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: What type of rear axle oil do I use? Yellow metal should not be a concern in the rear axle. Different story with transmissions. I would use GL-4 anyway if it were me. GL-4 and GL-5 do contain the same type of additives, but GL-5 contains a lot more. Last edited by JSeery; 07-05-2015 at 07:47 PM.

07-05-2015, 11:26 PM	#3
Drbrown Senior Member Join Date: Oct 2013 Location: Glens Falls NY Posts: 1,267	Re: What type of rear axle oil do I use? I use StayLub GL-4 90 or 140 .... ordered/purchased at my local NAPA store in Qt or Gallon containers. Some differential assemblies normally get hot during use and 140 may be preferred. Some use 140 if limited seepage is a problem. 140 is recommended for BW overdrives. Last edited by Drbrown; 07-05-2015 at 11:35 PM.

07-06-2015, 09:42 AM	#4
Ross F-1 Senior Member Join Date: Nov 2010 Location: NM Posts: 2,438	Re: What type of rear axle oil do I use? Many GL-5 EP gear oils have converted to additives that do not attack yellow metal. Walmart sells an 85w140 that says it is safe for use in axles and manual transmissions with copper-alloy parts. __________________ '52 F-1, EAB flathead

07-06-2015, 07:30 PM	#5
COE Dan Senior Member Join Date: May 2010 Location: Now in Wichita, KS Posts: 251	Re: What type of rear axle oil do I use? Thanks for the info. Dan

07-06-2015, 07:38 PM	#6
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: What type of rear axle oil do I use? Sponsored Links (Register now to hide all advertisements) I missed the 2-speed part when I first read your post. Not sure if they require anything different that a normal rear axle. Maybe someone can comment? Edit: Per Rotorwrench 4-07-2015: "Rear axle can use any straight grade SAE 90 or SAE 140 GL-4 or GL-5 lubricant. They can also use any multi-viscosity lube. The transmissions use GL-4. SAE 90 in cooler climates and SAE 140 in warmer climates. Sta-lube GL-4 can be purchased from a local NAPA dealer in straight grades. You can also use it in the Columbia 2-speed axle." Last edited by JSeery; 07-06-2015 at 07:57 PM.