SAE 90 vs 75-90W Synthetic Differential Oil
char...@darwin.sfbr.org
I can/should use a synthetic like Amsoil Series 2000 75-90W in my 1992 Mazda
MPV (4 Cylinder). The owners manual calls for SAE 90 above -18C (and it
doesn't even get close to -18C where I live in San Antonio Texas). Below
-18C it specifies SAE 80W.
I probably won't do any towing, but who knows. In the last cycle I did
do about 6K miles of towing (moving to San Francisco and back). Amazingly
this little 4cyl is rated to tow 2500 pounds, and I tested that limit.
Normally, I'd try to use an exact synthetic replacement, but I haven't seen
any synthetic diff oil in SAE 90. They all seem to be multigrades. Amsoil
does have an 80W-90, but that doesn't seem much different than 75W-90.
I had always thought that single grades were superior in some way (as with
SAE 30 which I use in my Engine, as specified). Multigrades were a kind of
compromise.
I notice that Amsoil has 3 applicable grades. Is it worth getting the
"race proven Series 2000"? Or would one of the others be as good or
better:
SAE 80W-90
SAE 75W-90
Series 2000 75W-90
Series 2000 75W-140
I think the Mobil diff oil is 75W-90 or maybe even a wider spread.
PS. I've seen the "not API certified" thread. If someone cares to comment
more about that, please give more specifics. Would I be better with another
synthetic such as Mobil (isn't that API certified?). What is API
certification anyway? Isn't Amsoil tested by someone? Does that differ
between their regular oils and the heavier diff oils? If you care to
comment, please give facts not flames.
I'm on my second batch of Amsoil
auto transmission fluid, and it seems great. I wouldn't bother with Amsoil
for my engine since I change that so frequently (but I used Amsoil engine
oil while towing when I figured I needed all the help I could get). But
for something that doesn't get changed frequently, synthetic seems like a
good idea, and it doesn't add much to the cost.
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Gary Derian
much difference. I would use standard 90W GL-4 or GL-5 per your owners
manual. If you lived in a cold climate, the 75W-90 would give better
economy when driving at low temps. For a rear axle, the main benefit of a
synthetic is that it stays thinner at low temps, hence the 75W-90 rating.
Since you don't have that problem, synthetic will be no help to you.
--
Gary Derian <gde...@cybergate.net>
char...@darwin.sfbr.org wrote in message
<73t7je$c1l$1...@nnrp1.dejanews.com>...
Pete Prunskunas
anti-chatter ingredient (mainly sulphur, it seems), while some other
synthetic gear oils like Valvoline specifically state that their oil is not
okay for limited slip rear ends (gotta add the extra anti-chatter fluid).
The Mobil 1 oil is 75w-90.
An interesting side-note: my 1998 GMC service manual states that for
the biggest version of the Sierra (3500 size, dualie, limited slip), under
really severe duty (towing heavy loads), the rear end oil should be
changed at 3000 miles with dino oil, while the interval is 30,000 miles
using synthetic oil. Viva la difference!
Pete
> I'm going to be replacing my differential oil this week. I'm wondering if
> I can/should use a synthetic like Amsoil Series 2000 75-90W in my 1992 Mazda
> MPV (4 Cylinder). The owners manual calls for SAE 90 above -18C (and it
> doesn't even get close to -18C where I live in San Antonio Texas). Below
> -18C it specifies SAE 80W.
>
> Normally, I'd try to use an exact synthetic replacement, but I haven't seen
> any synthetic diff oil in SAE 90. They all seem to be multigrades. Amsoil
> does have an 80W-90, but that doesn't seem much different than 75W-90.
>
> I had always thought that single grades were superior in some way (as with
> SAE 30 which I use in my Engine, as specified). Multigrades were a kind of
> compromise.
>
John Schmidt
>I'm going to be replacing my differential oil this week. I'm wondering if
>I can/should use a synthetic like Amsoil Series 2000 75-90W in my 1992 Mazda
>MPV (4 Cylinder). The owners manual calls for SAE 90 above -18C (and it
>doesn't even get close to -18C where I live in San Antonio Texas). Below
>-18C it specifies SAE 80W.
>
>I probably won't do any towing, but who knows. In the last cycle I did
>do about 6K miles of towing (moving to San Francisco and back). Amazingly
>this little 4cyl is rated to tow 2500 pounds, and I tested that limit.
>
>Normally, I'd try to use an exact synthetic replacement, but I haven't seen
>any synthetic diff oil in SAE 90. They all seem to be multigrades. Amsoil
>does have an 80W-90, but that doesn't seem much different than 75W-90.
>
>I had always thought that single grades were superior in some way (as with
>SAE 30 which I use in my Engine, as specified). Multigrades were a kind of
>compromise.
>
>I notice that Amsoil has 3 applicable grades. Is it worth getting the
>"race proven Series 2000"? Or would one of the others be as good or
>better:
>
>SAE 80W-90
>SAE 75W-90
>Series 2000 75W-90
>Series 2000 75W-140
>
>I think the Mobil diff oil is 75W-90 or maybe even a wider spread.
>
>PS. I've seen the "not API certified" thread. If someone cares to comment
>more about that, please give more specifics. Would I be better with another
>synthetic such as Mobil (isn't that API certified?). What is API
>certification anyway? Isn't Amsoil tested by someone? Does that differ
>between their regular oils and the heavier diff oils? If you care to
>comment, please give facts not flames.
>
>I'm on my second batch of Amsoil
>auto transmission fluid, and it seems great. I wouldn't bother with Amsoil
>for my engine since I change that so frequently (but I used Amsoil engine
>oil while towing when I figured I needed all the help I could get). But
>for something that doesn't get changed frequently, synthetic seems like a
>good idea, and it doesn't add much to the cost.
>
>-----------== Posted via Deja News, The Discussion Network ==----------
>http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
http://www.lubriplate.com shows the different viscosities of the
various gear oils. For instance, 90 weight gear lube is the same as
50 weight engine oil and 75W gear oil correspnonds to 10W engine oil.
Interesting reading.
API is the initials of the American Petroleum Institute. For a
lubricant to be API certified, the lubricant must meet or exceed
certain minimum API standards. The label might say "This oil meets
or exceeds" yada yada yada. The different oil suppliers pay big bucks
for the SAE donut.
The Eaton axle and transmission people fill some of their big truck
transmissions with synthetic fluid. No change necessary for 500,000
miles. Cummins Engine Company does not recommend the use of synthetic
engine oil unless the ambient air temperature is consistantly at or
below 13 degrees below zero F. (I think it's 13 degrees) Anyway,
that's too danged cold for me to be trucking around with ANY kind of
equipment. These particular comments don't have anything to do with
your question; they just point out different strokes for different
fokes.
John Feiereisen
wrote:
<snip>
>API is the initials of the American Petroleum Institute. For a
>lubricant to be API certified, the lubricant must meet or exceed
>certain minimum API standards. The label might say "This oil meets
>or exceeds" yada yada yada. The different oil suppliers pay big bucks
>for the SAE donut.
Correction: The oil companies pay $825/year (plus $0.00125/gal/year
for every gallon over one million) to participate in the API's Engine
Oil Licensing and Certification System and place the API 'donut' on
the oil bottles. This small fee covers *all* a company's certified
formulations, and the licensing agreement can be amended at no cost to
cover any new formulations that are commercialized later.
The oil companies pay big bucks to *test* their oils. The cost of
certification is insignificant in comparison.
--
John
Note: Email address munged in an attempt (probably futile) to
foil spammers. There are no digits in the real address.
y_...@hotmail.com
rat...@hotmail.com (John Schmidt) wrote:
> On Mon, 30 Nov 1998 04:40:14 GMT, char...@darwin.sfbr.org wrote:
> >PS. I've seen the "not API certified" thread. If someone cares to comment
> >more about that, please give more specifics. Would I be better with another
> >synthetic such as Mobil (isn't that API certified?). What is API
> >certification anyway? Isn't Amsoil tested by someone? Does that differ
> >between their regular oils and the heavier diff oils? If you care to
> >comment, please give facts not flames.
AFAIK - gear/diff lubricants are NOT API certified per se. The only API
certification process I know of for lubricants is the API's EOLCS process,
which only applies to engine oils. The API has certain standards for gear
lubes (API GL-4, GL-5, etc.) and it's up to a manufacturer to prove its
products meet said standards. For any gear oil, all you really have is the
word of the manufacturer.
> API is the initials of the American Petroleum Institute. For a
> lubricant to be API certified, the lubricant must meet or exceed
> certain minimum API standards. The label might say "This oil meets
> or exceeds" yada yada yada. The different oil suppliers pay big bucks
> for the SAE donut.
There are SOME oils that may or may not meet the standards, and don't
have the certification marks.
> The Eaton axle and transmission people fill some of their big truck
> transmissions with synthetic fluid. No change necessary for 500,000
> miles. Cummins Engine Company does not recommend the use of synthetic
> engine oil unless the ambient air temperature is consistantly at or
> below 13 degrees below zero F. (I think it's 13 degrees) Anyway,
> that's too danged cold for me to be trucking around with ANY kind of
> equipment. These particular comments don't have anything to do with
> your question; they just point out different strokes for different
> fokes.
Well - I've seen Valvoline Premium Blue 15W-40 at an auto parts store.
It's expressly made for use in Cummins engines and is approved by Cummins.
Valvoline claims that it meets certain API grades, but it doesn't carry
the API donut. But since the manufacturer expressly recommends this product,
I guess it's OK.
Yu-Ping Wang
Santa Clara, California