How to identify the fluid in a rear end.

SDE · Sep 20, 2019

As the years go by, technology gives us better products to use than what the owners manuals recommended 50 years ago. Is there a way to find out what is in a tractors rear end?
I drained a Farmall C and the fluid was a tan color. I thought that I would see what was in a Massey Harris 44 parts tractor. After the water came out, I got some much better looking fluid that I think might be a hydraulic fluid. It had a reddish color to it, and it wasn't as thick as I would have thought a 90wt oil should have been. Is there a way to test it to see what it is? PH strips? Anything else to try?
TY
SDE

Janicholson · Sep 20, 2019

YOu can pay to have it analyzed, but The C should have 80-90 gear oil, or 85-140 GL4. They are noisy even then. Jim

jCarroll · Sep 20, 2019

https://www.blackstone-labs.com

ohiojim · Sep 20, 2019

my guess is, if it's tan colored it probably has a little water in it. never saw any tan differential oil.

ss55 · Sep 20, 2019

If it only holds a few gallons, just replace it with new oil so you know for sure it has the correct oil.

jon f mn · Sep 20, 2019

Why bother testing unless you want to know if there are metal shavings and what they are. If you are wondering about the correct oil look in the book and use that or as close as you can get today. Most of that vintage tractor used 80/90 in the rear end and transmission.

KJohnson92 · Sep 20, 2019

It's best to look up the original spec online, and then replace it with a quality modern replacement. So, for example, if it called for 90 weight, use 80w90 conventional, or better yet, 75w90 synthetic. Also flush it out with diesel until it comes out clean, and then let it sit so any excess moisture can evaporate. Otherwise your new fluid will be milky right away again.

aFORDable · Sep 20, 2019

Like Ohiojim said, tan color means water has gotten in the oil, likely from a leaky gearshift boot or condensation over years. I'd change it and put a new gearshift boot on it if needed and keep it under shed if possible. After draining it you might want to flush it out before adding new oil. I've done that with a Massey before with good results.

dpendzic · Sep 20, 2019

yes--you can send out samples of oil for an analysis--i do it all the time on my Cat equipment

caterpillar guy · Sep 21, 2019

Smell should give you an idea of what you have in there. Mineral 90 will smell different than regular gear 90 and both will smell different than hyd/trans oil. You could also put your finger in it then touch to your tongue they do have a different taste to them. Put a sample in the freezer for a few hours then check how they pour the stiffness of the oil should give a hint of it also.

SDE · Sep 21, 2019

Due to the fact that I do not have any gear oils to compare this lube to, I will not be able to do a taste or smell test. I might try the freezer test though.
TY
SDE

SDE · Sep 21, 2019

With a cheap 5 gal bucket at $82, I might give the oil analysis test a try.($28)
TY
SDE

How to identify the fluid in a rear end.

SDE

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Janicholson

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jCarroll

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ohiojim

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ss55

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jon f mn

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KJohnson92

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aFORDable

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dpendzic

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caterpillar guy

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SDE

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SDE

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