A NEW TEST is described for studying the oxidation stability of automatic transmission fluids (ATF). The test shows an excellent correlation with transmission oxidation tests and points out the importance of time as a variable in such studies.
Carefully controlled automobile dynamometer tests have been used to study the shear stability of ATF's. Data are presented showing a comparison of driving conditions, transmissions, and V.I. improvers on shear stability. Results are related to the 50-hr Hydra-Matic durability test.
The poor reproducibility of rubber swell measurements on commercial transmission seals is due largely to differences in the rubber compounds. A great improvement in the reproducibility may be made by taking into account the specific gravity of the rubber sample.*