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1985 Ford F-800 Rear Axle and Transmission

Duromax04

Duromax04

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Can anyone tell me where I can find the weight and how much oil the Eaton Rear Axle holds in my F-800?
I cannot find any information on the capacities, and what weight gear oil it takes. There is a number stamped on it, 100954-C.

On the transmission, it has a Dana/Spicer 5 speed. I drained the oil out of it thinking it had gear oil in it, but it doesn't. It appears to have 50wt non-detergent, or something like that. Does anyone know if that is correct? Does anyone know where I can find this information. Having very little luck finding anything.

Thank You,
 
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Birken Vogt

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4-5 gallons in the axle and a little less in the transmission. Fill it till it is level with the hole.

Rear axles take 80W-90 below 100F or 85W-140 above 100F. Minmium temp is -15 on the 80W and -10 on the 85W. Or you can use 75W for extreme cold.

Transmissions generally specify SAE 50 engine oil.

I have given the specs for mineral oil. Synthetic oil is generally used these days and gives wider temperature ranges but probably a waste of money for you.
 
Duromax04

Duromax04

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Thanks for the Info.
I figured out that the transmission used SAE 50 transmission oil. I actually found a truck stop close buy that had bulk synthetic 50 wt Mobil Delvac Trans Fluid, so I took some jugs over there and had them fill them up. It took 6qts to get it to the hole.

On the rear end, it took 4 gallons. I used Synthetic 75/140 oil in it, because the cost difference wasn't all that much different and they had enough of it to get the job done.

Both drain plugs had magnets on them and there was a lot of metal attached to each of them. It wouldn't surprise me if neither of those have ever had the fluid drained before. Hopefully they both have good service life left in them. With a tiny engine like the 370 in there, they should'n't have had to much torque on them.
 
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Birken Vogt

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With synthetic you should never need to change them again, and not worry about temperature extremes either, not that anybody does anyway.
 
Truck Shop

Truck Shop

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A small bit of info-On early transmissions and/or any transmission with brass internal parts Synthetic oils can cause damage over time to the brass parts.
 
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Birken Vogt

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Truck Shop said:
A small bit of info-On early transmissions and/or any transmission with brass internal parts Synthetic oils can cause damage over time to the brass parts.
Click to expand...

I thought that piece of info applied to using stinky 80W-90 gear oil in transmissions, not synthetic/non-synthetic, but I will always defer to you.
 
Duromax04

Duromax04

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I hope it doesn't hurt anything, I guess time will tell. This truck is not going to get used to much. I bought to move a pile of dirt 6 miles round trip, so hopefully it will hold on for that. I have no idea how many trips it will take to get it moved, but I am guessing a lot.

Thanks for the info.
 
Truck Shop

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Birken Vogt said:
Do you have a link to manufacturer info on brass parts and synth oil? Because I can't find anything about it.

https://cglapps.chevron.com/sdspds/PDSDetailPage.aspx?docDataId=406142&docFormat=PDF

Lower right column first page it seems to indicate it is OK for copper and brass.
Click to expand...

I'm in the same boat you are, the only way I knew was from a oil analysis on a Clark 5 five speed that had heavy brass content. And was told subsequently about using Synthetics
where there is brass parts. Even our Shell distributor didn't know anything about it until he talked to a shell specifications rep. So there you have it, like many things these days
info happens by happenstance. And that is the best I can tell you.

And what I read in the link was copper no mention of brass.
 
Last edited:
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Birken Vogt

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I just read "copper containing parts" as copper and alloys that contain copper.

I also hate it when people tell me things. Show it in writing I say. Take it back to the source material.

The way I understand it, the stinky sulfur compounds in gear oil attack and corrode the copper and brass in transmissions. I have seen sulfurous gases attack copper and brass pipes and fittings as well. Since none of that is necessary or present in MT oils, I just figured it was a non-issue. The whole idea of synthetic oil is to need less additives to do the job. Oh well.
 
fast_st

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Duromax04 said:
I hope it doesn't hurt anything, I guess time will tell. This truck is not going to get used to much. I bought to move a pile of dirt 6 miles round trip, so hopefully it will hold on for that. I have no idea how many trips it will take to get it moved, but I am guessing a lot.

Thanks for the info.
Click to expand...
Your vin number might be helpful in decoding the axle code, often trucks had springs added or subtracted to fit a purpose, can go by tire sidewall load rating but a full box of dirt will likely be a healthy load. Give it a hot supper and a good run to shake out any bugs or mice. Sometimes dealers given the vin can come up with a build sheet from Ford.
 
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