Using a GL-5 in a GL-4 spec transmission

[supercity]

I contacted Penrite for their view. They said I bought the right product (GL-4 manual trans) and that their GL-5 manual trans fluids were not recommended.

I really like the sound of that Motul 300. If I double the power output of my engine maybe I can justify the expense.

 

[mechtech2]

Originally Posted By: antiqueshell
Originally Posted By: mechtech20


Except that GL4 has the same destructive sulfur as GL5. [Only 1/3 or so as much.]

.


And the reason why the car makers specify the GL-4 is for just that reason, the parts were engineered to withstand that amount of negative residue from sulfurous byproducts..but no more than that. So essentially the parts subject to
GL-4 as the manufactures specify will suffer NO ill effects for hundreds of thousands of miles.

Can you show me a non premium GL-5 product that clearly states that is will NOT damage yellow metals used in gearboxes that specify GL-4?

I'm not interested in spending a lot of money for gear box oil, you shouldn't have to anyhow.


Show you a non premium gear oil that is always suitable?
What a loaded and biased question!
Since when are we relegated to using only crud oils?
You wouldn't use a non premium gear oil, and neither would most anyone else.
Honest to goodness, what a weak proposition!

 

[MolaKule]

Quote:
Is it possible they have formulated the GL-5 fluid with additives that are not detrimental to soft metal syncros?


Some of you guys are still missing the point.

GL-4 is a level of protection rating for gears and is generally applied to manual transmissions and to manual transaxles that do not have hypoid designs.

The older formulations in GL-4 MT lubes had about 1200 to 1500 ppm of phosphorous and zinc or ZDDP as the primary Anti-Wear additive. Some simply contained a lower level of phosphorous-sulfur EP additives like those used in differential (GL-5) lubes.

GL-4 MT lubes don't need a strong EP additive level like the phosphorous-sulfur EP levels in a differential lubricant because of the type of gearing and gear-tooth loading.

If you care to read the White Papers you will see that gear lubes, whether GL-4 or GL-5, have more than just Anti-Wear (AW) or Extreme-Pressure (EP) additives.

ALL Gear lubes contain anti-rust, anti-foam, and Metal Deactivator chemistries.

Metal Deactivator chemistries are chemical compounds that keep an additive component or contaminant from reacting with metals in the gear box.

The important thing to keep in mind about the Specific Application GL-4 MT lubes is that they contain the proper friction modifier chemistries to assist with better shifting and synchro engagement.

Personally, I relegate GL-5 rated lubes to hypoid differentials only.