What kind of axle gear oil to use on 5 ton

[Vintage iron]

I just did my all my inner axle seals on my M813. the drums, brake shoes and wheel cylinders were new. But someone screwed up the inner axle seals putting the hubs back on. Everything is put on with tips from SS. I haven't seen what kind of gear oil to use to fill the axle back up to the proper level. The fluid I have in the axles now, is a yellowish color and doesn't smell to much. I want to get the same kind so I am not mixing different gear oils. What is the civilian name and info.

 

[Jones]

Yellowish doesn't ring a bell here. Honey-colored and cloudy is often oil with water mixed in (emulsified).
Attached is the TB on oils and fuels. It doesn't say much about civilian or brand names but it's good information just the same.

 

[Vintage iron]

No! It is not cloudy. I was told that it maybe synthetic oil. I heard, that you don't want to mix synthetic oil with non synthetic oil. If it is synthetic oil can I just drain the axles and use civilian gear oil? I have the manuals for my truck and the LO. They list the Mil-spec oil but I am sure my supplier won't know anything about it.

 

[jasonjc]

GL-5 80-90wt grear oil. And some does/will have the mil spc listed on the container. But it all depends I've the small bottle have all the spec number and good info on the bottle but the 5 gal pail won't say much of nothing on it.

 

[Vintage iron]

Thanks JasonJC! What color is it? Still trying to figure out what is in my axles. I will buy it from a big truck supply, so it will be in five gallon buckets or bigger.

 

[jasonjc]

Looks like gear oil/motor oil. Smells diferent than motor oil though.

 

[pwrwagonfire]

GL-5 80-90wt grear oil. And some does/will have the mil spc listed on the container. But it all depends I've the small bottle have all the spec number and good info on the bottle but the 5 gal pail won't say much of nothing on it.

Yeah 80/90 is the way to go...I believe the stuff I got for my M-37 is "Mil spec," I got Valvoline brand

 

[Vintage iron]

Yes JasonJC my axle gear oil looks like motor oil but it only has a little gear oil smell. I think it, must be synthetic. I hear that synthetic oils are much more expensive! I also hear that you can't switch back from synthetic oils.

The questions are: (1)Is this synthetic gear oil in my axles?
(2)If so what should I run to top them off?
(3)if you don't want gear oil in your hubs, why do we fill the axles so high? The ring gear dips way down in the oil and brings it up anyways,right?

 

[mckeeranger]

The questions are: (1)Is this synthetic gear oil in my axles?
(2)If so what should I run to top them off?
(3)if you don't want gear oil in your hubs, why do we fill the axles so high? The ring gear dips way down in the oil and brings it up anyways,right?

1. Don't know without seeing it. Sorry.
2. Same.
3. Between some big gears and the counter drive assembly, it needs a lot of oil. You don't want to suck a "hole" in the oil driving down the road and toast everything.

 

[Ord22]

the on highway trucks of today use the synthetic 80/90w oil. there is nothing wrong with using this oil. its expensive than the other. you can't mix them at all. the synthetic run cooler in the diffs. it saves on the wear and tear of the gears.

 

[Vintage iron]

Thanks for all the help. I am pretty sure that my axle gear oil is synthetic. I am going to take sample with me to the truck supply company to confirm! I will let everyone know how I make out.

 

[paulfarber]

Yellowish doesn't ring a bell here. Honey-colored and cloudy is often oil with water mixed in (emulsified).
Attached is the TB on oils and fuels. It doesn't say much about civilian or brand names but it's good information just the same.

This is seriously out of date. You really should not post it. Using old, superseded lubes can cause problems if the mechanic is not aware of the newer spec and uses and old, out of date one as you posted.

 

[paulfarber]

Thanks for all the help. I am pretty sure that my axle gear oil is synthetic. I am going to take sample with me to the truck supply company to confirm! I will let everyone know how I make out.

Synthetic oils don't run cooler. They last longer and withstand more heat, but they do little to reduce the temp of a meshing component. They are no more 'slippery' than regular oil (before you get all uppity remember a pound of lead weighs the same as a pound of feathers... 30wt oil is 30wt oil).

80/90 wt has been pretty much a standard since the 40's. The 140wt oil was to think and until then 'learned' how the lighter oils affected things mostly they would leak because they were much thinner and many seals on mechanical assembly's were still leather. 80/90wt got a really bad rap at first.

 

[Vintage iron]

Hey, Paul The TM and LO are not much help because I haven't seen anything that states if the oil is Synthetic or non-synthetic. The other members are just trying to help out with their experience they have. If you find a manual or LO are out of date. Maybe you should post which one members should go to. I would have thought that others would have had the small clear golden gear oil in their axles too, but I haven't received any help on this part. Any ideas how do identify the fluid that is my axles? What should Mil-spec non-synthetic gear oil look like? What should Mil-spec synthetic gear oil look like?

Let's keep this civil. No one here is getting uppity.

 

[Vintage iron]

I spoke to a great local guy who has lots of experience with military vehicles of all kinds. He said that it is definitely synthetic and I should be able to mix other synthetic oils with what I have. He told me to check my transmission too. So if you have thinnish golden gear oil that doesn't smell to much in your axles, chances are that it is synthetic. He said that he runs 75-90w synthetic in his trucks. I will still take a sample with me to see if I can match up the gear oil, I like to keep the same brand and weight in the axles if possible. It is safer that way. Worse case, I can drain one and use it to top off the rest. That way only one has a mixture in it.