30RH/32RH/36RH/37RH 3-Speed

Fig. 1 Automatic Transmission W/lock-up Torque Converter:

Fig. 2 Automatic Transmission W/Lock-Up Torque Converter:

30RH & 32RH Automatic Transmission.:

These transmissions, Figs. 1 through 3, combine a torque converter with a fully automatic three speed gear system. The converter housing and transmission case are an integral aluminum casting. The transmission consists of two multiple disc clutches, an overrunning (one-way) clutch, two servos and bands and two planetary gearsets to provide three forward speeds and reverse.

The common sun gear of the planetary gearsets is connected to the front clutch by a driving shell that is splined to the sun gear and to the front clutch retainer.

The hydraulic system consists of a single oil pump and a valve body that contains all the valves except the governor valve

Venting of the transmission is accomplished by a drilled passage through the upper part of the front pump housing.

The conventional torque converter is a three element unit consisting of a front cover, impeller, turbine, stator, and stator overrunning clutch. The converter is attached to the crankshaft through a flexible driveplate. A lock-up torque converter is used with most transmissions. It is similar to the conventional unit in that the turbine, impeller, and stator are employed, however the lock-up converter has an internal mechanism for locking the turbine and impeller in direct drive. In a conventional converter there is some slippage between turbine and impeller in direct drive. Locking these components eliminates this slippage, resulting in improved fuel economy and reduced fluid temperatures.

The lock-up system consists of a lock-up mechanism within the converter, a lock-up module attached to the valve body, and a switch valve in the valve body. The switch valve is actually the converter control valve which has been modified for lock-up system use.

Fig. 4 Cross-sectional View Of Conventional & Lock-up Torque Converter:

The converter internal lock-up mechanism uses sliding clutch piston, torsion springs, and clutch friction material, Fig. 4. The friction material is attached to the front cover, the clutch piston is mounted in the turbine, and the torsion springs are located on the forward side of the turbine. The torsion springs dampen out engine firing impulses and absorb shock loads that occur during lock-up.

Fig. 5 Lock-up Torque Converter Operation:

When the transmission reaches a predetermined speed, transmission fluid is channeled through the input shaft and into the area between the clutch piston and turbine. The fluid pressure forces the piston against the front cover friction material, locking the turbine to the impeller, Fig. 5. When the vehicle speed decreases or the transmission shifts out of direct drive, fluid pressure is released, the clutch piston retracts, and the converter operates in a conventional manner. The converter is cooled by circulating the transmission fluid through an oil-to-water type cooler located in the radiator lower tank. The torque converter is a welded assembly and is not serviceable.

Do not attempt to interchange lock-up and conventional converters. The transmission input shaft and valve body used for lock-up operation are different. Because the lock-up mechanism is completely enclosed within the converter, lock-up converters have an identifying decal attached to the front cover. The decal is circular in shape and states converter type and stall ratio.

Fig. 6 Wide Ratio Planetary Gearset:

All 32RH transmissions, Fig. 6, are equipped with a wide ratio gearset. Low gear ratio is 2.74 to 1. The sun gear and front planetary gearset is unique to the wide ratio transmission. The rear planetary gearset remains the same as previous transmission models.