In 1998, Toyota releases the Genuine Automatic Transmission Fluid ATF Type T-IV Fluid Specification (JWS3309). This fluid was the Next Generation High-Performance ATF for Slip-Controlled Automatic Transmissions. This fluid replaces Type T-III, Type T-II and Type T fluids in all vehicles. All vehicles produced after 1993 with Automatic Transmissions specified to use ATF Type T, T–II and T–IV.
Type T-IV fluid is backward compatible with the previous Type T fluid. For example, Type T-IV can replace Type T-II fluids; however, they should not be mixed.