A/T - E4OD Description and Operation
9209ford02
Article No.
92-1A-6
01/26/92
TRANSMISSlON - E40D-NEW 4-SPEED AUTOMATIC OVERDRIVE TRANSMISSION - DESCRIPTION AND OPERATION INFORMATION
LIGHT TRUCK: 1989 E-250, E-350, F SUPER DUTY, F-250, F-350
ISSUE: The E40D is a new 4-speed automatic overdrive transmission. The E40D transmission was derived from the C-6 automatic (3-speed) transmission.
ACTION: Use the following information to familiarize yourself with the various E40D components. This information can help you explain the operation of the transmission to the customer.
The E40D uses electronic controls to control shift points, pressure regulation and torque converter clutch control. This provides high quality shifts, good fuel economy and overall performance. The engine and transmission are monitored with diagnostic testing available through the EEC-IV Quick Test. The E40D operations are provided by both operator selected positions of the manual selector lever and with an overdrive cancel switch located on the instrument panel.
FUNCTIONS
P (Park), R (Reverse), and N (Neutral) are the same as other Ford automatic transmissions.
D (Overdrive - normal driving position) provides all automatic shifts through fourth gear (overdrive) along with application and release of the converter clutch. The transmission may also be shifted manually between all forward ranges.
D (Overdrive - with overdrive cancel switch activated, amber light on. This position is selected by pushing the switch on the instrument panel.) provides all automatic shifts, including the application and release of the converter clutch, except the shift into overdrive. It is used to provide additional engine braking for descending grades.
2 (Manual second) provides only second gear operation regardless of vehicle speed. It is useful for start-up on slippery surfaces or to provide engine braking on downgrades.
1 (Manual low) provides only low (1st) gear at start-ups. At higher speeds it results in a downshift to second gear followed by an automatic downshift to low which occurs when vehicle speed decreases enough. Once in low, the transmission will stay in low until the selector is moved to another position.
ELECTRONIC CONTROL
The E40D is electronically controlled by a microprocessor known as the EEC-IV processor (electronic control assembly, ECA). The EEC-IV processor controls both the engine and the transmission on gasoline engine applications in the same microprocessor. On diesels the ECA controls the transmission only. Electronic control also provides powertrain system diagnostic capabilities which will result in earlier and more accurate resolution of E40D malfunctions. Service technicians can detect many types of transmission concerns if they occur during the standard EEC-IV "Quick Test" on both gas and diesel use. Additionally, the overdrive cancel switch indicator light will flash during certain conditions which will inform the driver to go to a Ford dealer for servicing.
The processor gathers information from sensors located throughout the vehicle which are monitoring vehicle operating conditions. Using this information, the processor determines the best operating state for the transmission. A solenoid body assembly, containing five solenoids, receives the processor signals which in turn produces the desired mode of operation.
Altitude compensation for shift quality and cold ambient warm-up strategy are also provided in the electronic controls. This eliminates the need for changes to the transmission for operating in mountainous regions. It also allows the E40D to operate effectively even in extreme cold.
An overdrive cancel switch allows lockout of overdrive with the push of the switch. The switch is located on the instrument panel and is useful for providing increased engine braking on downhill grades. Depressing the switch will lock out overdrive (amber light turns on). Pressing it again, will change the system back to normal operation. Whenever the ignition key is turned on, the vehicle will automatically provide overdrive operation regardless of the switch position the last time the vehicle was running.
FUNCTIONAL COMPONENTS
Components from the intermediate brake drum rearward to the output shaft and extension housing seal are similar to the C-6 automatic transmission. However, the E40D planetary gears have a higher contact ratio for quieter operation. Forward of the intermediate brake drum, the E40D components are new. These new parts are:
^ Center support assembly
^ Overdrive ring gear
^ Coast clutch
^ Overdrive sun gear and planet gear assembly
^ Pump and support assembly
^ Converter and clutch/damper assembly
The E40D has wider forward gear ratios than the C-6 as shown below.
GEAR C-6 E40D
First 2.46 2.71
Second 1.46 1.538
Third 1.00 1.00
Overdrive --- 0.712
Reverse 2.18 2.18
Currently there are 12 E40D models for use in F-250/350 (4x2 and 4x4), Econoline (5.8L/7.3L Diesel/7.5L) and F Super Duty (7.3L Diesel/7.5L). For details in diagnosing, testing, disassembling and assembling, see Section 17-09 of the 1989 Truck Shop Manual. Also see the E40D Theory and Diagnosis Technical Training Manual (Order No. 1710-012). The E40D, like the C-6, is filled with Mercon fluid. The fluid should be changed every 30,000 miles for severe service use.
OTHER APPLICABLE ARTICLES: 89-9-18
WARRANTY STATUS: INFORMATION ONLY
OASIS CODES: 590000