After reading a lot, I decided that there was not real conclusion to be found on what has been previously discussed. So here is a Poll/Thread with the intention of finding a definitive answer.

If you have something intelligent to say, please post.

If you have been using a particular product, please elaborate with name, price, quality, time used, etc.


What is the best Synth. Trans Oil for the SS/SC, and why?

Thanks Guys,
GP

Bump for conclusive poll!

 

bump.. cuz i wanna change my tranny oil next time I change my engine oil... nice thinking of starting a poll

 

ive heard to only use the factory stuff

 

Apparently, you can get significant gain in smoothness by switching to Royal Purple. I am interested in changing as soon as I get a definitive answer.

Yeah, but Royal Purple has a reputation for being a lot better than the standard. The standard is the the Saturn option in the poll.

 

Max Gear 75W-90 is the only Royal Purple Product that meets the GL-4 requirement GM has set. Syncromax while it may work is still not the right product for the SS/SC!

 

Quote:
Originally Posted by rockkrawler628
bump.. cuz i wanna change my tranny oil next time I change my engine oil... nice thinking of starting a poll

Apparently, you can get significant gain in smoothness by switching to Royal Purple. I am interested in changing as soon as I get a definitive answer.

yeah def... I changed out the tranny fluid in my jeep with royal purple and it made a big diff. i should have done it a lot earlier to prevent the grinding of shitty syncros but owell its gone now...
bump for some more people

 

castrol makes the saturn fluid and also makes a synthetic 75w90 and says that they are not compatible and the saturn fluid has no equivalents

 

Exactly why I use 75W-90 Max Gear Oil. My tranny shifts smoother then any other tranny I have ever had.

 

I know Castrol sent you that email, but it is possible for there to be better products out as I'm sure they can't possibly keep track of every competitors products. Other 75W-90's don't meet the GL-4 requirement and are indeed not equivalent to the Saturn Manual Tranny Fluid! However, the Royal Purple Max Gear does! In fact it actually meets the GL-4 and GL-5 requirements which is even better! Grab a bottle and read the back of it at the parts store, and then look at all the other stuff on the shelves. Nothing else compares period, and to top that off I can confirm as well with many others that it works great and it a ton smoother than the Saturn stuff. Plus, it has the shock protection additive as well a special LSD additive. It's almost like they formulated the stuff specifically for our cars!

Since I'm on my third tranny from breaking two third gears, I went the extra mile to ensure this one lasts a long time. To me the $10/bottle Max Gear was worth a whole hell of a lot more and then some! I don't recommend products so highly unless I've proven they perform and I will never guide anyone down the wrong path!

 

Thanks for the discussion guys, this is the issue I wanted to clear up.


What is the GL-4 and Gl-5? I emailed Royal Purple about this, I will post up my findings later.


Check this out, maybe another possibility:
http://www.syntheticwarehouse.com/synthetic_gl4.htm

 

That looks like a new viable alternative as well! Good find as AMSoil makes great products as well!

 

This is the first response from Royal Purple:


Adrian,

The Cobalt SS 2.0 L engines with manual transaxles use a GM 21018899 spec fluid. We had our lab analyze the Saturn MTF and recommend using RP 10W40 Motor Oil or XPR 10W40 Motor Oil.

Another alternative would be Max Gear 75w90, but it is slightly heavier.

This transaxle takes 2 quarts.

Have a great day.

Kyle Neal
Technical Sales Representative

 

I run Synchromax in my trans... for about 4months now... love it. 75w-90 in a manual seems really heavy how can running 10w-40 be ok and then also 75w-90..... the weight of those are night and day....

 

Hmmm... I need new trans oil as well. But I was looking at Amsoil and Redline products.

 

yea i will be changing mine to AMSOIL here soon, i run their motor oil and it's good stuff!

 

Keep us posted on how it works out for you!

 

I use the RP max gear 75w-90, and i love it. Nice smooth shifts, never had a grinding problem with my tranny since ive switched to it.

I highly recommend the Royal Purple max gear 75w-90. Ive actually had a gm tranny tech tell me that its better than the factory stuff, and suggested i use it instead of the factory stuff.

 

will do! it will be awhile before i change it, i'll prolly wait til my next oil change which is still 1,500 miles away

 

So after a lot of research this is the short of what I found.

API or American Petroleum Institute is the trade institute who in collaboration with companies like GM developed the GL standard. These GL standards are modeled after military (Department of Defense) oil use standards.

Although API developed, and uses the GL standards, it is ASTM International (American Society for Testing Materials) who continues to do the actual testing: http://enterprise.astm.org/WORKITEMS/WK4651.htm

From API:

1 Introduction
This document was prepared by the Lubricants Committee
of the American Petroleum Institute to assist manufacturers
and users of automotive equipment in the selection of
transmission, transaxle, and axle lubricants for the operating
conditions described.

3.2 API GL-4
The designation API GL-4 denotes lubricants intended for
axles with spiral bevel gears operating under moderate to severe
conditions of speed and load or axles with hypoid (see
note)gears operating under moderate speeds and loads.
These oils may be used in selected manual transmission and
transaxle applications where MT-1 lubricants are unsuitable.
The manufacturerŐs specific lubricant quality recommendations
should be followed.
Although this service designation is still used commercially
to describe lubricants, some test equipment used for
performance verification is no longer available. Procedures
to define this performance are currently being reviewed for
adoption by ASTM.
Note: Frictional requirements for axles equipped with limited-slip differentials
are normally defined by the axle manufacturer.

3.3 API GL-5
The designation API GL-5 denotes lubricants intended for
gears, particularly hypoid (see note) gears, in axles operating
1
Lubricant Service Designations for Automotive Manual Transmissions,
Manual Transaxles, and Axles
under various combinations of high-speed/shock load and
low-speed/high-torque conditions. Lubricants qualified under
U.S. Military Specification MIL-L-2105D (formerly
MIL-L-2105C) satisfy the requirements of the API GL-5 service
designation, although the API designation does not require
military approval. Performance test details are in
ASTM Publication STP-512A.
Note: Frictional requirements for axles equipped with limited-slip differentials
are normally defined by the axle manufacturer.



Basically:

The different GL standards show that the oil is good for specific uses. I think GL-5 is best for the Cobalt, from all that I have read.

Now there is the matter of viscosity, etc.

 

I just ordered the Amsoil...

 

What is Synchromax? 10w-40?

 

I use Royal Purple Max-Gear Oil 75W90. Glass smooth shifts, no grinding at all. Made an actual noticeable difference.

I wouldn't use any other Royal Purple product. You are not suppose to use any ATF in the SS/SC, which both the RP Max ATF and RP Synchromax are.

 

Thats what I heard. In one of my posts above, the Sales Tech from Royal Purple recommended the Max Gear.

I think this is rather definitively answered.

The only other thing now, is alternatives like AMSOIL or w/e

 

Quoted from the Redline Oil website...

Gear Oil viscosity is not the same as Engine oil Viscosity.

70W80 Gear Oil = 5W30/10W30 Engine Oil

 

Very, very interesting.