Acronyms and Definitions: Transmissions

NOTE: The transmission naming convention is as follows:

The first character, a number, is the number of forward gears.
The second character, either the letter "F" or "R," represents front (transaxle) or rear (transmission) wheel drive.
The next set of characters, a grouping of numbers, represents the design torque capacity of the transmission/transaxle (for example, "27" represents 270ft./lbs. in the 4F27E transaxle).
The last character, if used, is one of the following:
- "E" for electronic shift
- "N" for non-synchronous shift
- "S" for synchronous shift
- "W" for wide ratio

4F27E : Also known as the FN Focus automatic transmission.

4F44E : Formerly known as the CD4E.

4F46S : Formerly known as the AX4S and regular-duty AXOD-E.

4F50N : Formerly known as the AX4N and heavy-duty AXOD-E.

4R44E : Formerly known as A4LD for 3.0L applications.

4R55E : Formerly known as A4LD for 4.0L applications.

4R70W : Formerly known as AOD-E.

4R100 : Formerly known as E4OD.

5R44E : Formerly known as A5LD for 3.0L applications.

5R55E : Formerly known as A5LD for 4.0L applications.

5R55N : Lincoln LS automatic transmission.

5R55W : Wide-ratio truck transmission.

4x4L : 4x4 Low.

A/T : Automatic Transmission.

CCS : Coast Clutch Solenoid.

CCSF : Coast Clutch Solenoid Fault. Displays a YES if fault exists.

EPC, EPC1, EPC2 : Electronic Pressure Control.

EPCV : Electronic Pressure Control Volts.

ESS : Electronic Shift Scheduling.

HCDSS : High Clutch Drum Speed Sensor. PCM input from the 4R44E and 4R55E.

ISS : Intermediate/Input Shaft Speed Sensor.

M5OD : Manual 5-Speed transmission with overdrive (RWD).

M/T : Manual Transmission/Transaxle.

NPS : Neutral Pressure Switch or its signal input to the PCM.

OCS : Overdrive Cancel Switch.

OSS : Output Shaft Speed. Indicates rotational speed of the transmission output shaft.

PNP : Park/Neutral Position switch. Also known as Neutral Drive Switch (NDS), Neutral Gear Switch (NGS), and Transmission Switch Neutral (TSN).

REVERSE or REV : Transmission Reverse Switch Input.

SIL : Shift Indicator Lamp. A lamp that indicates the preferred shift points on select manual transmission/transaxle vehicles.

SS1/SS2/SS3 : Shift solenoids. Devices that control the shifting in an automatic transmission.

TCC/TCCH : Torque Converter Clutch. When energized, causes a mechanical engagement and disengagement of the Torque Converter Clutch.

TCIL : Transmission Control Indicator Lamp. Indicates that the TCS has been activated.

TCS : Transmission Control Switch. Modifies the operation of electronically controlled transmissions.

Torque converter : A device which by its design multiplies the torque in a fluid coupling between an engine and transmission/transaxle.

TFT : Transmission Fluid Temperature. Indicates temperature of transmission fluid.

Transaxle : A device consisting of a transmission and axle drive gears assembled in the same case. Front-wheel drive applications.

Transmission : A device which selectively increases or decreases the ratio of relative rotation between its input and output shafts. Rear-wheel drive applications.

TR, TR1, TR2, TR3, TR4 : Transmission Range. The range in which the transmission is operating.

TR Sensor : Formerly known as Manual Lever Position Sensor (MLPS). Provides information to the PCM on the transmission range selector position.

TR V : Transmission Range Voltage.

TSS : Turbine Shaft Speed. Indicates rotational speed of the transmission turbine shaft.

VSS : Vehicle Speed Sensor. A magnetic pickup device that generates an AC signal that is proportional to vehicle speed.