System Description

DESCRIPTION




48RE Transmission







The 48RE is a four speed fully automatic transmissions with an electronic governor. The 48RE is equipped with a lock-up clutch in the torque converter. First through third gear ranges are provided by the clutches, bands, overrunning clutch, and planetary gear sets in the transmission. Fourth gear range is provided by the overdrive unit that contains an overdrive clutch, direct clutch, planetary gear set, and overrunning clutch.


The transmission contains a front, rear, and direct clutch which function as the input driving components. It also contains the kickdown (front) and the low/reverse (rear) bands which, along with the overrunning clutch and overdrive clutch, serve as the holding components. The driving and holding components combine to select the necessary planetary gear components, in the front, rear, or overdrive planetary gear set, transfer the engine power from the input shaft through to the output shaft.


The valve body is mounted to the lower side of the transmission and contains the valves to control pressure regulation, fluid flow control, and clutch/band application. The oil pump is mounted at the front of the transmission and is driven by the torque converter hub. The pump supplies the oil pressure necessary for clutch/band actuation and transmission lubrication.


IDENTIFICATION






Transmission identification numbers (1) are stamped on the left side of the case just above the oil pan gasket surface. Refer to this information when ordering replacement parts.


GEAR RATIOS

The 48RE gear ratios are:
1st -2.45:
2nd -1.45:
3rd -1.00:
4th -0.69:
Rev. -2.20:1