GL-4 gear oils are most often used in older gear sets, including truck applications where the loads are not very heavy as well as older automobiles. GL-4 gear oils also find some application in heavily loaded, non-offset industrial gear sets.

In its comments on the ballot, Chevron stated that it agrees with nearly all of the points made by ExxonMobil regarding why GL-4 should be obsolete. (In May, Kevin Buzdygon of ExxonMobil Research & Engineering had pointed out that it is impossible to run most tests for GL-4 performance, and some of the tests have been unavailable for over 14 years.) Going further however, Chevron said that a complete overhaul of API 1560 is needed, not just this one change.

Chevron, represented in the Lubricants Group by Matthew Ansari, said it too is frustrated by the fact that GL-4 is commonly used to designate a level of performance which cannot be defined by existing test methods. However, it said, API cannot simply declare GL-4 to be “not in current use” since API doesn’t set the specification — ASTM does. API 1560 just describes automotive gear lubricant service designations, which assist manufacturers and users of automotive equipment in the selection of gear lubricants, based on gear design and operating conditions. Where special performance requirements apply, the API descriptions reference the automotive lubricants test language developed by ASTM in standard STP 512A.

The oil marketer also pointed out that the categories of “Service Designations in Current Use” and “Service Designations not in Current Use” were established in 1995, when API 1560 last was updated. Even back then, ASTM document STP 512A acknowledged that GL-4 oils were technically obsolete because the test equipment used to define the specification was no longer available. However, because API felt that many OEMs and others in the industry were actively using the designation, it chose to leave GL-4 in the “Current Use” category.

Chevron believes that GL-4 is still widely accepted in the industry, particularly in the manual transmission and tractor hydraulic fluid areas. Therefore, it urged that GL-4 remain in the “Current Use” category. It also pointed out that continued listing of GL-4 in this manner says nothing about whether or not the specification still exists; only that it is valuable as a general description of applications for which a GL-4 gear oil is intended.

The company went on to state that API 1560 needs a complete rewrite, to address this and a number of other changes in gear oil standards that aren’t included in the current document. In particular, the MT-1 and GF-5 gear oil standards have been fully defined by ASTM but API 1560 does not reflect this.

Chevron also strongly recommended that the API Lubricants Group consider taking a more active role in gear oil qualifications, currently managed by SAE. It said the SAE system is overly expensive, burdensome and has serious technical deficiencies. At present, it noted, the industry cannot achieve any approvals because hardware used to test gear oils is “out of control.”

API’s Lubricants Group is trying to set a time and date to review this ballot result, discuss and resolve Chevron’s disapproval and come to a final agreement on the next steps.