This document has been declared "Stabilized" and will no longer be subjected to periodic reviews for currency. Users are responsible for verifying references and continued suitability or technical requirements. New technology may exist.

This SAE Recommended Practice is intended as the definition of a standard test, but may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use.

The SAE No 2 Friction Test Machine is used to evaluate the friction characteristics of automatic transmission plate clutches with automotive transmission fluids. It can also be used to conduct durability tests on wet friction systems.

The specific purpose of this document is to define a Durability Test based on a specific power level selected from either the 3600 r/min Stepped Power Test or from the 6000 r/min Stepped Power Test, for the evaluation of wet friction system performance variation as a function of number of cycles. This standard procedure is intended for common use by both suppliers and end users to allow objective comparisons of wet friction material system performance.

The only variables selected by the supplier or user of the friction system are: a. Friction Material; b. Fluid; and c. Reaction Plates.

These three variables must be clearly identified when reporting the results of this test. If any of the test parameters or system hardware as described in this document are changed, other than the friction material, test fluid, or reaction plates, the data may not be reported as having been obtained using this document.

This procedure is not intended to evaluate the initial coefficient or break-in characteristics. For this information, refer to SAE J2490 SAE No. 2 Friction Test Machine \gmPVT Test.