How does the overdrive engage, and where is it located?
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How does the overdrive engage, and where is it located?
E4OD means, E=Electronic----4=Four gears forward----OD=Overdrive----4th gear is OD with a ratio of 1:.75, the transmission output turns one revolution for every 3/4 revolution of the engine.
The E4OD is electronically controlled by a microprocessor known as the EEC-IV processor (electronic control assembly, ECA).
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.
The shift lever (MLPS, Manual Lever Position Sensor), mounted on the transmission, sends a signal to the ECA to determine P-R-N-D-1-2.
The FIPL mounted on the IP throttle shaft sends a signal to the ECA.
The VSS sends a signal to the ECA showing how fast your going, MPH.
The tach sensor sends a signal to the ECA showing what RPM the engine is turning.
The EEC processor takes all these signals and selects which solenoid in the transmission to energize.
At approx 27 MPH , the Torque convertor will lockup, which puts the engine and transmission in direct drive 1:1 ratio.
At approx 37 MPH, the OD clutch pack internally is engaged depending on what signal the FIPL is sending to the ECA.
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Last edited by OLDBULL8; 06-26-2012 at 07:47 AM.
Okay, I have heard that OD works in conjuction with 3rd, is this true? Or is it actually a separate gear?
Reverse works with third. Fourth is a seperate gear set.
Coming soon Studs, turbo, and a 4R100. 
(The yard goat) 
Aha. Okay, thank you.
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