Main Components and Functions

Torque Converter

The torque converter (7902) is a four-element converter. It contains the standard three elements that transmit and multiply torque:

• Impeller.
• Turbine.
• Reactor.
• Torque converter clutch.

The torque converter clutch increases fuel economy in 3rd and 4th gears.

The operation of the torque converter components is as follows:

• Rotation of the converter housing and impeller set the fluid in motion.
• The turbine reacts to the fluid motion from the impeller, transferring rotation to the geartrain.
• The reactor redirects fluid going back into the impeller, allowing for torque multiplication.

The addition of a torque converter clutch to the torque converter provides a mechanical link between the converter housing and the engine, allowing for direct transfer of power from the engine to the geartrain.

The torque converter clutch is applied and released by fluid pressure, which is controlled by the powertrain control module (PCM) (12A650) through a torque converter clutch solenoid (TCC solenoid) (7G136) in the main control valve body (7A100).

Impeller and Cover

The primary functions of the impeller and cover assembly are to drive the impeller blades, contain hydraulic fluid and provide a mating surface for the converter clutch pressure plate. In addition, the impeller hub drives the fluid pump gear.

Turbine

The turbine is a sectioned, donut-shaped steel stamping that is splined to the input shaft. It is driven by fluid from the impeller and transmits this power to the geartrain. Because of its basic shape, the turbine automatically directs fluid back to the impeller.

Reactor

The reactor redirects the fluid flow returned to the impeller from the turbine so that the fluid moves in the same direction as engine/impeller rotation. This action aids in torque multiplication because it adds torque to that already supplied by the engine. The reactor contains a one-way clutch that holds it stationary when torque multiplication is necessary, but allows freewheeling at higher speeds when torque multiplication is not necessary.

Torque Converter Clutch

The pressure plate attaches to the back of the turbine and can be applied against the cover to allow for a mechanical transfer of engine torque to the geartrain. This occurs mainly in third and fourth gears when torque multiplication is no longer necessary. (Converter clutch application may also occur in second gear under certain conditions.)

The pressure plate works much like a regular mechanical clutch. Apply, release and controlled slip of the clutch are controlled by opposing fluid forces on each side of the pressure plate.

Torque Converter Sectional View

Item	Part Number	Description
1	—	Torque Converter Cover (Part of 7902)
2	—	Turbine (Part of 7902)
3	—	Impeller (Part of 7902)
4	—	Reactor (Part of 7902)
5	—	Torque Converter Clutch (Part of 7902)

Geartrain

Input Shaft

The input shaft (7017) is supported by two bushings in the stator support. End positioning of the input shaft is controlled by the splines in the converter turbine and the overdrive planetary carrier.

Output Shaft

The output shaft (7060) is supported by two bushings in the case and by the slip yoke bushing in the extension housing. End positioning is controlled by the parking pawl gear and snap ring or shoulder and by the reverse ring gear hub and snap ring.

Overdrive System

The overdrive planetary system consists of the overdrive planetary carrier, overdrive sun gear (7D063), overdrive ring gear, coast clutch cylinder, overdrive one-way clutch assembly and the center shaft as shown in the following illustration. The overdrive planetary carrier is splined to the input shaft. The overdrive sun gear is centered by a bushing on the input shaft and laterally held in place by needle bearings on the reactor support and the overdrive planetary carrier. The overdrive sun gear is splined to the coast clutch cylinder, which in turn is splined to the overdrive one-way clutch inner race.

The outer race of the one-way clutch is splined to the overdrive ring gear which is splined to the center shaft. The center shaft is centered by the forward planetary assembly and is laterally held by needle bearings on the center support and the overdrive planetary carrier. The center shaft is splined into the forward clutch cylinder.

Two friction clutches are assembled in the overdrive planetary assembly. The coast clutch is splined between the coast clutch cylinder and the overdrive ring gear. The coast clutch is activated to perform engine braking in Manual 1, Manual 2 and 3rd gear with the transmission control switch engaged.

The overdrive clutch is splined between the case and the coast clutch cylinder. The overdrive clutch holds the coast clutch cylinder and, in turn, the overdrive sun gear to permit the planetary carrier to overdrive the ring gear.

Item	Part Number	Description
1	377300-S	Ring — Retaining (Attaches Gear Assembly — O/D Sun to Cylinder Assembly — Coast)
2	7A658	Shaft — Overdrive Center
3	7D483	Ring — Overdrive CL Pressure Plate Retainer (Selective Fit)
4	7D063	Gear Assembly — Overdrive Sun
5	377155-S	Ring — Retaining (Attaches Clutch Assembly — O/D One-Way to O/D Ring Gear)
6	377135-S	Ring — Retaining (OWC to Outer Race)
7	7A089	Clutch Assembly — Overdrive One-Way
8	7L339	Washer — Overdrive — Overrun Clutch Thrust No. 3
9	7B446	Planet Assembly — Overdrive
10	7F240	Bearing Assembly — Overdrive Planet — Thrust No. 4
11	7A153	Gear — Overdrive Ring
12	7G375	Ring — Retaining (Retaining Center O/D Shaft Assembly to O/D Ring Gear)
13	7G178	Bearing Assembly — Overdrive Center Shaft — Thrust No. 5

Center Support and Intermediate/Overdrive Clutch Cylinder

The center support provides a pilot for the forward clutch and direct clutch cylinders. Also provides fluid for clutch application and lube flow. The center support is radially and laterally held by the case. Fluid supply enters through feed bolts into the center support and supplies the forward clutch and the intermediate lube circuits. The direct clutch is fed by the center support.

The intermediate/overdrive clutch cylinder is radially supported by the case. Laterally, the cylinder is held in the case by a snap ring. The overdrive circuit is fed through a feed bolt into the cylinder. The intermediate clutch circuit is fed through nearby orifices.

Item	Part Number	Description
1	7D483	Ring — Overdrive CL Pressure Plate Retainer (Selective Fit)
2	7B442	Plate — Overdrive Clutch External Spline — Steel
3	7B066	Plate — Overdrive Clutch Pressure
4	7B164	Plate — Overdrive Clutch Internal Spline — Friction
5	7A527	Ring — Overdrive Clutch Disc Spring — Retaining
6	7B070	Spring — Overdrive Clutch Piston Disc
7	7A262	Piston — Overdrive Clutch
8	7A548	Seal — Overdrive Clutch Piston — Outer
9	7F225	Seal — Overdrive Clutch Piston — Inner
10	7D483	Ring — Intermediate Cylinder Retaining
11	7D025	Seal — Direct Clutch Cast Iron (2 Req'd)
12	7B164	Plate — Intermediate Clutch Internal Spline — Friction
13	7Z059	Bolt — M10-1.5 x 24mm Overdrive Cylinder Fluid Feed
14	7G384	Cylinder — Overdrive and Intermediate Clutch
15	7F225	Seal — Intermediate Clutch Piston — Inner
16	7E005	Piston — Intermediate Clutch
17	7F224	Seal — Intermediate Clutch Piston — Outer
18	7B070	Spring — Intermediate Clutch Piston — Disc
19	7Z059	Bolt — M12-1.75 x 31mm Center Support Fluid Feed (2 Req'd)
20	7A130	Support Assembly — Center
21	7L326	Washer — Center Support Thrust No. 6
22	7B066	Plate — Intermediate Clutch Pressure — Apply
23	7B442	Plate — Intermediate Clutch External Spline — Steel
24	7B066	Plate — Intermediate Clutch Pressure — Rear

Forward Drive System

The forward drive system consists of the forward clutch cylinder, intermediate brake drum, intermediate one-way clutch, input shell, forward ring gear, forward ring gear hub, forward/reverse sun gear and the forward planetary carrier and forward planetary gears.

The forward clutch cylinder is splined on the center shaft. The forward ring gear is piloted on the forward ring gear hub. Thrust washers on the forward planetary carrier and forward clutch cylinder hold the forward ring gear hub in place.

The intermediate brake drum is radially supported by bushings on the center support and is laterally controlled by thrust washers on the forward clutch cylinder and center support. The intermediate brake drum has the inner race of the intermediate one-way clutch press fitted on its pilot. The intermediate one-way clutch's outer race is splined to the intermediate friction clutch, which is splined to the case. The intermediate brake drum has lugs that are slotted into the input shell to form a mechanical connection. The input shell is splined into the forward/reverse sun gear. The forward/reverse sun gear is common to two planetary gearsets. The forward planet is splined to the output shaft and is laterally positioned by needle bearings on the sun gear and on the forward clutch cylinder as shown in the following illustration.

Two friction clutch assemblies, the direct clutch and the forward clutch, are shown with the forward planetary assembly. The direct clutch assembly splines the forward clutch cylinder to the intermediate brake drum. The forward clutch assembly splines the forward clutch cylinder to the forward ring gear. The forward clutch is activated during all forward gears. While in third or fourth gear, both the direct and forward clutches are applied to hold the forward planetary assembly and enable it to act as a solid shaft.

In second gear, the intermediate clutch assembly holds the forward/reverse sun gears. It is applied, along with the intermediate one-way clutch, to hold the intermediate brake drum, input shell and forward/reverse sun gear. In higher gears, the one-way clutch overruns.

Forward Drive System Components

Item	Part Number	Description
1	7A089	Clutch Assembly — Intermediate One-Way
2	7G401	Washer — Intermediate One-Way Clutch — Thrust No. 7
3	7D044	Drum Assembly — Intermediate Brake
4	7A548	Seal — Direct Clutch Piston — Inner
5	7A548	Seal — Direct Clutch Piston — Outer
6	7A262	Piston Assembly — Direct Clutch
7	7F235	Retainer and Spring Assembly — Direct Clutch
8	7C122	Ring — Direct Clutch Support Spring Retaining
9	7C096	Washer — Intermediate Brake Drum — Thrust No. 8A
10	7B164	Plate — Direct Clutch Internal Spline — Friction
11	7D019	Seal — Forward Clutch Cylinder (2 Req'd)
12	7A548	Seal — Forward Clutch Piston — Outer
13	7B164	Plate — Forward Clutch Internal Spline — Friction
14	7B066	Plate — Forward Clutch Pressure — Rear
15	7D090	Washer — Forward Clutch Hub — Thrust
16	7B442	Plate — Direct Clutch External Spline — Steel
17	7B066	Plate — Direct Clutch Pressure
18	377126-S	Ring — Direct Clutch Pressure Plate Retaining (Selective Fit)
19	377127-S	Ring — Retaining
20	377128-S	Ring — Retaining
21	377437-S	Ring — Retaining
22	7F374	Bearing Assembly — Forward Clutch Needle — Thrust No. 8B
23	7A360	Cylinder Assembly — Forward Clutch
24	7A548	Seal — Forward Clutch Piston — Inner
25	7A262	Piston Assembly — Forward Clutch
26	7D256	Ring — Forward Clutch Piston Spring
27	7B070	Spring — Forward Clutch Piston Disc
28	377127-S	Ring — Forward Clutch Spring (FWD CL Piston Spring to FWD CL Cylinder Assembly)
29	7B066	Plate — Forward Clutch Pressure
30	7E085	Spring — Forward Clutch Pressure
31	7B442	Plate — Forward Clutch External Spline — Steel
32	377127-S	Ring — Forward Clutch Pressure Plate Retaining (Selective Fit)
33	377437-S	Ring — Retaining
34	377444-S	Ring — Retaining
35	386841-S	Ring — Retaining
36	386842-S	Ring — Retaining
37	377132-S	Ring — Forward Hub Retaining (FWD Ring Gear Hub to FWD Ring Gear) No. 8C
38	7B067	Hub — Forward Ring Gear
39	7D392	Gear — Forward Ring
40	7D234	Bearing Assembly — Forward Clutch Thrust (Between FWD Ring Gear and FWD Planet Assembly) No. 9A
41	7A166	Washer — Forward Planet Carrier — Thrust No. 10A
42	7A398	Planet Assembly — Forward
43	7D234	Bearing Assembly — Forward Clutch Thrust (Between FWD Planet Assembly and FWD Sun Gear Assembly) No. 9B
44	7D063	Gear Assembly — Forward/Reverse Sun
45	7D064	Shell — Input
46	7D066	Washer — Input Shell Thrust No. 14
47	377300-S	Ring — Retaining (Attaches FWD/REV Sun Gear Assembly to Input Shell)

Low-Reverse Drive System

The reverse planetary assembly consists of the reverse planetary carrier, reverse planet gears, the reverse ring gear, the reverse ring gear hub, the reverse clutch hub and the low-reverse one-way clutch assembly.

The reverse ring gear hub is splined to the output shaft and to the reverse ring gear. The reverse ring gear hub is laterally held by a needle bearing on the inner race of the low-reverse one-way clutch and a snap ring on the output shaft. The reverse planet (7D006) is splined to the low-reverse clutch hub. The low-reverse clutch hub is connected by the reverse clutch to the case and is pinned to the outer race of the low-reverse one-way clutch. The inner race of the low-reverse one-way clutch is piloted on and bolted to the case.

The reverse clutch assembly is activated in reverse gear and in manual one. The reverse clutch bypasses the reverse one-way clutch during coast and manual one. The reverse clutch holds the reverse planet in reverse gear to enable the sun gear to drive the reverse ring gear in the opposite direction.

Item	Part Number	Description
1	7E085	Spring — Transmission Reverse Clutch Cushion
2	377155-S	Ring — Reverse Planet Retaining
3	7A166	Washer — Planet Carrier Thrust (Between Reverse Planet Assembly and Input Shell) No. 10B
4	7D006	Planet Assembly — Reverse
5	7A166	Washer — Planet Carrier — Thrust (Between Reverse Planet Assembly and Output Shaft Hub) No. 11
6	387031-S	Ring — Retaining (Retaining Output Shaft Hub to Output Shaft Assembly)
7	7A153	Gear — Output Shaft Ring
8	7D164	Hub — Output Shaft
9	377132-S	Ring — Retaining (Retaining Output Shaft Hub to Output Shaft Ring Gear)
10	7B067	Hub Assembly — Reverse Clutch
11	7A089	Clutch Assembly — Reverse One-Way

Apply Components

The following information describes the operation of the three E4OD one-way clutches.

Overdrive One-Way Clutch

The overdrive one-way clutch, shown in the following illustration, transmits engine torque from the overdrive sun gear to the overdrive ring gear in 1st, 2nd and 3rd gear range. The overdrive one-way clutch transmits power when the sprags are engaged between the inner and outer races. The inner race is splined to the coast clutch cylinder, which in turn is splined to the overdrive sun gear. The outer race is splined to the overdrive ring gear.

The overdrive one-way clutch engages whenever the overdrive planetary system attempts to drive the overdrive sun gear clockwise when the overdrive ring gear has a counterclockwise torque from the vehicle. When torqued counterclockwise, the overdrive one-way clutch engages and acts as a wedge to lock the sun gear and the ring gear together. During coast, the overdrive one-way clutch enables the ring gear to overrun or spin at a faster rate than the sun gear.

The overdrive one-way clutch overruns when in overdrive (4th gear). In overdrive, the coast clutch cylinder is held by the overdrive one-way clutch, which in turn holds the overdrive sun gear. This causes the overdrive planetary carrier assembly to walk about the sun gear and overdrive the overdrive ring gear. The inner race of the overdrive one-way clutch is thus held stationary while the outer race is allowed to overrun clockwise.

Overdrive One-Way Clutch (Roller Design)

Intermediate One-Way Clutch

The intermediate one-way clutch, shown in the following illustration, holds the forward/reverse sun gear stationary relative to the case in 2nd gear. The outer race of the intermediate one-way clutch is splined to the intermediate clutch, which in turn is splined to the case. The inner race is pressed on the intermediate brake drum, which is connected to the sun shell. The sun shell is splined to the forward/reverse sun gear.

In 2nd gear, the intermediate clutch holds the outer race of the intermediate one-way clutch. Torque from the vehicle acts counterclockwise on the output shaft, and in turn the forward planetary carrier and the reverse ring gear. Torque from the center shaft is counterclockwise.

This combination applies a counterclockwise torque on the sun gear and likewise the intermediate one-way clutch. The intermediate one-way clutch engages, causing the forward ring gear to turn the forward planetary carrier clockwise at reduced speed. During coast, the intermediate one-way clutch allows the sun gear to spin clockwise as the engine rpm coasts down.

The intermediate one-way clutch overruns in 3rd, 4th and reverse gears. The direct clutch is engaged, causing the intermediate brake drum to rotate clockwise with the center shaft. With the intermediate drum rotating clockwise, the inner race also rotates clockwise, causing the intermediate one-way clutch to overrun.

In first gear, the outer race of the intermediate one-way clutch is not held, and the intermediate one-way clutch is overrunning.

Intermediate One-Way Clutch (Sprag Design)

Low-Reverse One-Way Clutch

The low-reverse one-way clutch, shown in the following illustration, holds the reverse planetary carrier stationary to the case in first gear. The inner race of the low-reverse one-way clutch is bolted directly to the case. The outer race is splined to the reverse clutch hub, which is splined to the reverse planetary carrier.

In first gear, the center shaft drives the forward ring gear clockwise by way of the forward clutch. With the forward planetary carrier providing a counterclockwise resisting torque, the forward/reverse sun gear is driven counterclockwise.

As the sun gear is turned counterclockwise and the reverse ring gear is turned counterclockwise by the resistance of the vehicle, the reverse planetary carrier is also turned counterclockwise. Because the reverse planetary carrier is prevented from turning counterclockwise by the low-reverse one-way clutch, the torque is transferred from the sun gear to the reverse ring gear and the output shaft. During coast, the planetary carrier is allowed to overrun and spin clockwise.

The low-reverse one-way clutch overruns in 2nd, 3rd and 4th gears. In these cases the forward/reverse sun gear are stationary while the reverse ring gear turns clockwise with the output shaft. This turns the reverse planetary carrier clockwise, causing the low-reverse one-way clutch to run clockwise and overrun.

Low-Reverse One-Way Clutch