General Information

Fig. 1 Ultradrive A-604 Transaxle:

The A-604 Ultradrive electronic four speed transaxle, is a fully adaptive, electronically controlled transmission. The A-604 transaxle uses feedback sensors to adjust functions on a real time basis, similar to an electronic anti-lock brake system.
The A-604 transaxle provides four forward speeds with ratios of 2.84:1, 1.57:1 1.00:1 and .069:1. Torque converter lock-up is available in second, direct, or overdrive gear. 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 the four forward speeds and reverse ratio. Electric solenoids provide the transmission's shift control. Sensors on the transmission input operating conditions to the electronic control unit located under the hood in a potted, diecast aluminum housing. The system can be diagnosed by accessing information from the electronic control unit memory. The transmission and differential sump have a common oil sump with a communicating opening between the two.