I purchased a 1990 F 350 cab and chassis to pull my camper with and when I checked the oil level in the rear axle and found it was the color of coffee with cream in it. I changed out the oil, and the gears looked good, but there seemed to be a lot of moisture in the axle, could this have caused the brown color of the oil? One other question, do I need to put an additive in the oil? I don't know for sure what kind of axle is in this truck but the code on the door is 65 and there was a tag on the axle that has V189C on one line and 4.10 10 2 9L01 on a second line below it, can any one help me with this problem, Thanks

Ken Gagas

 

Light brown color is usually normal, especially if this is the original lube in your 1990 truck. Moisture might have been caused by going through water or maybe condensation, but normally should not be there. What do you mean "a lot of moisture"?

On an F350 I would guess you have a limited slip so you probably will need to add the limited slip additive. I use StaLube TracLoc which meets Ford and GM Spec. Wait for one of the guys who decodes diff #s to confirm this.

Good Luck
Jim Henderson

 

Hey, Ken, when water gets into the axle lube it starts to turn the color and consistency of a chocolate milkshake. Since oil floats on top of water you might very well have a small puddle of moisture lurking in the bottom of that pumpkin. Probably a good time to change it anyway, the manual for my F-250 says to change it if it's been exposed to water, used under tough duty or anyway after 60,000 miles, no longer than 100,000 miles.

I wouldn't worry about it being a limited-slip or not, when you change the lube put in some of the friction-modifying additive for LS differentials, anyway. The synthetic lube I use in my own truck's axle has the additive already in it and it's suitable for use in limited-slips or not, either way.

 

I should clarify mu first statement a little. Brown lube is normal for lube that is used and has miles on it. New fluid should be honey color. Really dirty fluid might be black and fluid with a lot of moisture will look like a Chocolate Mousse.

Jim Henderson

 

Thanks for all the information, I've changed the oil in the axle and now all I have to do is add the additive to the oil. I'm sure it will be fine for an other 60,000 miles.

Thanks again for all your help.

Ken Gagas