manual transmission fluid

[pradtf]

i couldn't find a definite answer to what to use in the transmission beyond dextrall and not type 'f':
http://forums.amceaglenest.com/index.php?topic=6545.0
after looking all over the forums.

the tsm says use 85W90.

lordco sold me some pennzoil gearplus 80W90 gl-5 (they didn't have the other) and said the stuff is most popular with older cars. there is nothing on the container about type 'f' or not.

we have a 1981 eagle wagon manual trans.

so is it ok to replace whatever is in there with the 80W90 despite what the manual says?


i understand the first number gives the 'thickness' at cool temp while the second the 'thickness' at hot temp. therefore, since both are going to give 90 when the car is running (i guess), doesn't that make either fine?

[wagoneerhauler]

I'm not sure what trans model you have but the T5 I bought had ATF spilling out.

[IowaEagle]

What year is your Eagle and which transmission is it?   Dexron is automatic transmission fluid (ATF) and Type "F" is a transmission fluid for Ford automatics -- which you do not have if you have an automatic.  If you have an automatic transmission, then please do not put that gear oil in it, get some Dexron III or IV compatible fluid.  I am guessing you have a manual transmission which would cause some confusion as AMC got confused them selves as which was the best to use.

[eaglefreek]

Dextron which is ATF (automactic transmission fluid) is what you want to use. It's my understanding that AMC sent out an update to use ATF instead of gear oil.

[pradtf]

What year is your Eagle and which transmission is it?   Dexron is automatic transmission fluid (ATF) and Type "F" is a transmission fluid for Ford automatics -- which you do not have if you have an automatic.  If you have an automatic transmission, then please do not put that gear oil in it, get some Dexron III or IV compatible fluid.  I am guessing you have a manual transmission which would cause some confusion as AMC got confused them selves as which was the best to use.

thx for the explanation regarding atf and type'f'!

as indicated earlier, we have a 1981 eagle wagon manual trans.
the pennzoil gearplus 80W90 gl-5, i presume is automatic transmission fluid and not gearoil.
i asked for auto trans fluid and that's what they gave me.

will this be ok or should i be looking for dextron?

[IowaEagle]

85W - 90 is gear oil, really thick stuff and is what is recommended for the manual 4-speed in '81.   ATF or automatic transmission fluid is much thinner and red in color and has a distinct odor to it.  Gear oil, to me almost has a faint sulfur smell.   In 1982 AMC changed their minds and recommended ATF (Dexron II) for their manual transmissions.    So, I would check to see what is in there now and base your decision on that.

[BenM]

GL-5 is useable if your transmission has gear oil in it, but you really want GL-4 gear oil if that's what you're using. GL-5 is harder on brass synchros then GL-4.

If you have ATF in your manual, run ATF or get manual transmission fluid replacement. Some companies make a MTF that is a Dextron II/III substitute with a different set of additives specially designed to replace ATF in manual transmissions that call for ATF.

Unfortunately, it's not mix-and-match.

BTW, 80W90 is about like a 20W50 engine oil. A 75W90 is more like a 10W40. An ATF is more like a 5W30 or a 0W20 depending on spec. The numbers don't line up exactly, and that is only comparing weights. They are only interchangeable in very specific cases.

(Learned all this looking at fluid changes for the cars this spring.)

[pradtf]

ok thx both doug and ben for the oil scoop!
we'll get to the trans with more confidence now ... after we figure out the transfer case. at least we know that's just 10W30!

[AMCKen]

ok thx both doug and ben for the oil scoop!
we'll get to the trans with more confidence now ... after we figure out the transfer case. at least we know that's just 10W30!

If you're going to use 10w30, why not use 5w30. It flows better when cold and usually costs the same.

[wagoneerhauler]

I believe the t-case uses ATF.

[BenM]

I believe the t-case uses ATF.

It changed over the years. Early specs were 10W30, later ones were ATF.

[wagoneerhauler]

Do you know the year they changed?

[IowaEagle]

IIRC 10W 30 was used in the NP 119's and then with the advent of the NP 129 and 128, ATF was used.

[wagoneerhauler]

OK by model then.  I'll have to watch out for that.  The 229s use ATF or the Jeeps that I had them in do/did.

[IowaEagle]

Makes sense the 229's used ATF too.