Solenoid operation Archives - Transmission Digest
Hydraulics Fundamentals: Clutch Regulator Valves

Knowing how these circuits work and the slightly different variations that the manufacturers utilize should pinpoint any valve body-related issues

Volkswagen’s Direct-Shift Gearbox Part 3

Although the DSG 02E transmission contains 11 solenoids, they could be placed into three categories: gear actuator, pressure control and TCC. This article covers the first group and part of the second, and next month’s article will cover the rest of the second group and the third.

Operation Multi-Select

The shift strategy of Chrysler’s 45RFE and 545RFE transmission is clever and unique. The computer controls a total of seven solenoids in the transmission to perform all shift-feel, shift-timing, converter-clutch-apply and failsafe strategies.

Ford 4F27E Shift Strategy – a Different Way of Doing Things

The 4F27E transmission uses two on/off solenoids and three PWM solenoids to produce each of the shifts and converter-clutch apply, as the chart in Figure 1 shows. The EPC solenoid is used to control line pressure relative to engine torque. So far this sounds easy, but from a strategy standpoint, it progressively moves toward a “different way of doing things” when compared with what we are accustomed to.

Load-Testing Solenoid Circuits

The last thing I want to do is put you to sleep with an article on performing electrical tests and Ohm’s Law. What I want to show here is something that I think is really exciting: load-testing solenoid circuits with an ammeter! Using an ammeter and a calculator can save time, LOTS OF TIME. How would you like to check the power distribution, ignition switch, external and internal wiring, solenoids, computer and computer grounds without putting the vehicle on a lift or even raising the hood?