Overdrive and Coast Clutch System

WARNING: This page is about a different car, the 2006 Ford Pickup, 2006 Ford F550 Super Duty, 2006 Ford F450 Super Duty, and 2006 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

The overdrive (OD) and coast clutch system consists of the following:

OD friction clutch assembly
Coast clutch cylinder
Overdrive sun gear
Coast clutch input hub
Coast clutch friction clutch assembly
OD planetary
OD ring gear
Center shaft

The OD clutch piston has bonded lip seals. It is installed into the piston bore, cast into the pump and held in place by the return spring. The return spring is attached to the pump with 3 bolts. The OD clutch separator plates and pressure plate are splined to the case. The 3 OD friction plates are splined to the coast clutch cylinder. The OD clutch assembly is positioned between the pump face and a snap ring, and installed into the case adjacent to the OD pressure plate. The OD sun gear is pressed into the coast clutch cylinder.

The coast clutch piston is also a bonded lip seal type. The coast clutch piston is installed into the coast clutch cylinder and held to the cylinder along with the clutch return spring by a snap ring. The separator plates are splined to the case.

The coast clutch pressure plate is a mechanical diode one-way clutch (OWC) assembly. The OWC is splined to the coast clutch cylinder and held in with a snap ring. The coast clutch friction plates are internally splined to the coast clutch hub, which is held to the OD carrier by 4 bolts. Absorbing the load between the OD carrier and the OD sun gear is the "captured" thrust bearing, part of the OD planet assembly.

On the opposite side of the OD planet is a thrust bearing positioned between the carrier and the shaft. The OD ring gear is splined to the center shaft and retained by a snap ring. On the opposite side of the center shaft is a thrust bearing that separates it from the center support. The overdrive/coast clutch system is driven clockwise by the input shaft, one end of which is splined to the torque converter cover, and the other end is splined to the OD carrier.

Center Support and Intermediate Clutch

The center support is rigidly held to the case by a tapered snap ring. The flat side faces toward the center support and the gap at 6 o'clock. The center support is also retained to the case by 2 hollow feed bolts. Both the forward clutch feed bolt and the intermediate clutch feed bolt are installed through the solenoid body worm trail of the case. The forward feed bolt has an orifice plug installed on top of the bolt head.

The center support acts as the intermediate clutch cylinder piston bore, and also provides the snap ring groove to retain the bonded seal type intermediate clutch piston and the return spring. A black phenolic thrust washer is positioned by its 2 tabs into 2 holes in the center support. A seal pack containing 2 Teflon® seals is pressed onto the center support hub below a pressed-on steel sleeve. The sleeve acts as the journal for the direct clutch cylinder bushings.

The intermediate clutch separator plates and pressure plate are externally splined to the case and the friction is internally splined to the direct clutch cylinder. The case and the center support define and limit the stroke of the intermediate clutch.