Carla said:
Where would I go about checking the PCM pressure? For future reference, what are MPLS and PCM acronyms for?
MPLS= Manual Position Lever Sensor
From the service manual (c. 1994):
The manual lever position sensor (MLP sensor):
Is transmission-mounted.
The powertrain control module (PCM) (12A650) monitors the voltage across a series of step-down resistors that corresponds to the position of the manual control lever (7A256). The powertrain control module uses this information in determining desired gear and EPC pressure.
Permits the engine to start only in the PARK and NEUTRAL positions.
Activates the back-up lamps in the REVERSE position.
PCM=Powertrain Control Module
From the service manual (c. 1994):
The powertrain control module (PCM) (12A650) performs the following functions:
Accepts inputs from various engine sensors to compute the required fuel flow rate necessary to maintain a prescribed air/fuel ratio throughout the entire engine operational range.
Then the powertrain control module outputs a command to the fuel injectors (9F593) to meter the appropriate quantity of fuel.
Determines and compensates for the age of the vehicle and its uniqueness.
Automatically senses and compensates for changes in altitude (i.e. from sea level to mountains).
From what I've read, there's an additional pressure test tap on the 4R70W that tests EPC solenoid pressure. From the service manual (c. 1994): This Pinpoint Test is intended to diagnose the following components: Transmission Wiring Harness, EPC, EPCPWR, and Powertrain Control Module (PCM).
As to how to check the pressure, I cannot help much, but there's a line pressure tap on the housing that one can test pressure at. I cannot verify this on the 1985 transmission, though....