Ford 8N transmission/hydraulic oil?

[Roger_N]

I made a trip to Tractor Supply company yesterday and they were out of the
gear oil "for older Ford tractors". I've been reading about what oil to use
and am left a bit confused. If I understand correctly, I can use 90W GL1,
or GL3 but not GL5 because GL5 is bad for brass parts in the hydraulic pump.
Also, I could use Universal Transmission Hydraulic Fluid that is recommended
to replace Ford M2C134D (or something like that). The UTHF is a lot
lighter, something like 10W-20, than the 90W specified. I kind of like the
GL3 option since it's near the right weight and has a mild EP (mild
extreme?) rating.

Any recommendations on what fluid to use that is not too difficult to find?

Thanks!

RogerN

[Don Young]

Post by Roger_N
I made a trip to Tractor Supply company yesterday and they were out of the
gear oil "for older Ford tractors". I've been reading about what oil to
use and am left a bit confused. If I understand correctly, I can use 90W
GL1, or GL3 but not GL5 because GL5 is bad for brass parts in the hydraulic
pump. Also, I could use Universal Transmission Hydraulic Fluid that is
recommended to replace Ford M2C134D (or something like that). The UTHF is
a lot lighter, something like 10W-20, than the 90W specified. I kind of
like the GL3 option since it's near the right weight and has a mild EP
(mild extreme?) rating.
Any recommendations on what fluid to use that is not too difficult to find?
Thanks!
RogerN

I have no specific knowledge or recommendations for your oil, but I do know
that not all oils use the same viscosity numbers. That is to say: 90W gear
oil is a whole lot lighter than 90 weight motor oil would be. I think 90W
gear oil is about equal in viscosity to 30 or 40 weight motor oil. Oil which
is too thick can be worse than that which is too thin, especially in
hydraulic systems. This may or may not help in your choices.

Don Young

[vredsdfr]

Post by Don Young
I think 90W
gear oil is about equal in viscosity to 30 or 40 weight motor oil.

That I cannot believe. I'm thinking about my body work days and I
don't see 90W gear oil running through my viscosity cup as quick
as 30/40W motor oil.

[Roger_N]

Post by Don Young
I have no specific knowledge or recommendations for your oil, but I do
know that not all oils use the same viscosity numbers. That is to say: 90W
gear oil is a whole lot lighter than 90 weight motor oil would be. I think
90W gear oil is about equal in viscosity to 30 or 40 weight motor oil. Oil
which is too thick can be worse than that which is too thin, especially in
hydraulic systems. This may or may not help in your choices.
Don Young

In some of my reading up on the subject, I read that gear oil weight was
rated at something like 150 degrees and motor oil was weight was rated at
around 210 degrees. I was wondering if 40 weight non-detergent motor oil
would be close to what I need for the tractor.

[moray]

Post by Roger_N

Post by Don Young
I have no specific knowledge or recommendations for your oil, but I do
90W gear oil is a whole lot lighter than 90 weight motor oil would be. I
think 90W gear oil is about equal in viscosity to 30 or 40 weight motor
oil. Oil which is too thick can be worse than that which is too thin,
especially in hydraulic systems. This may or may not help in your
choices.
Don Young

In some of my reading up on the subject, I read that gear oil weight was
rated at something like 150 degrees and motor oil was weight was rated at
around 210 degrees. I was wondering if 40 weight non-detergent motor oil
would be close to what I need for the tractor.

In something that age, provided it's wet, slippery, reasonably thick, and
doesn't contain sulphur (that's the key ingredient of EP oils, that causes
them to attack brass), it'll do the job. You're not talking something with
high precision components, where oil choice is highly critical.

As for the gearoil viscoscity. The W indicates that viscoscity is measured
at the low temperature (roughly 20degC IIRC), wheras no W means it's taken
at the hot temp (60degC IIRC - I'd have to dig out my old college notes to
make sure).

[David V.]

Post by moray
As for the gearoil viscoscity. The W indicates that viscoscity
is measured at the low temperature (roughly 20degC IIRC),
wheras no W means it's taken at the hot temp (60degC IIRC -
I'd have to dig out my old college notes to make sure).

That's right. The "W" stands for "Winter" not weight or
viscosity. The "Winter", as said above, means it held it's
viscosity while cold.