A604 4-Speed

Fig. 1 Cross sectional view of Ultradrive A-604 transaxle:

The A-604 (41TE) Ultradrive electronic four speed transaxle is a fully adaptive transaxle using feedback sensors to adjust functions on a real time basis, similar to electronic anti-lock brake controls.
The A-604 transaxle provides four forward speeds with ratios of 2.84:1, 1.57:1 1.00:1 and .069:1, with torque converter lock-up available in second, direct, or overdrive gears. Reverse ratio is 2.21:1. The A-604, Fig. 1, consists of three multiple disc input clutches, two multiple disc grounded clutches, four hydraulic accumulators and two planetary gear sets to provide four forward speeds and reverse ratio. Electrical solenoids provide transaxle shifting control. Sensors on the transaxle send control inputs to the Electronic Control Unit (ECU) located below the hood in a potted, diecast aluminum housing. The system can be diagnosed by accessing information from ECU memory. The transaxle and differential sump have a common oil sump with a communicating opening between the two.