4R100 PWM Solenoid Block for Ford 1998-Up 76991B

4R100 PWM solenoid block for Ford applications equipped with the matching 4R100 automatic transmission. This replacement assembly is for the PWM torque converter clutch configuration and uses OEM reference number 76991B for part identification.

Confirm that the original transmission uses the PWM solenoid-block design before ordering. The 4R100 was available with PWM and non-PWM torque converter clutch systems, and these solenoid blocks are not interchangeable. Match the original part number, connector style, solenoid layout, and transmission configuration.

Part Details

• Part type: Automatic transmission solenoid block assembly

• Transmission application: 4R100

• Control type: PWM torque converter clutch configuration

• Application range: 1998-up, subject to transmission configuration verification

• OEM reference number: 76991B

• Vehicle compatibility: Ford applications equipped with the matching 4R100 PWM transmission

• Quantity: One solenoid block assembly

Fitment And Identification

This solenoid block is for 4R100 PWM applications only. Ford used more than one 4R100 solenoid-block configuration, including PWM and non-PWM torque converter clutch designs.

Verify all of the following before ordering:

• Transmission is a Ford 4R100 automatic transmission

• Existing solenoid block uses PWM torque converter clutch control

• Electrical connector and solenoid arrangement match the removed unit

• OEM reference number 76991B matches the service application or original component

• Vehicle application is confirmed by VIN, transmission tag, or qualified parts catalog

For early 1998 applications, configuration verification is especially important. PWM fitment began on diesel applications during 1998, while gasoline applications may require confirmation before selecting a PWM solenoid block. By 1999, PWM use became the standard 4R100 configuration.

Service Guidance

Use this component when diagnosis identifies a failed, contaminated, sticking, or electrically out-of-specification solenoid block. Potential symptoms can include harsh shifting, delayed or erratic engagement, shift flare, converter clutch concerns, slipping, or transmission-related fault codes. These symptoms may also result from damaged wiring, poor electrical connections, valve-body wear, low or degraded fluid, internal transmission damage, or control-system faults.

Inspect the transmission case connector, internal harness, valve body, and related components before installation. Follow the correct Ford service procedure for solenoid-block installation, transmission fluid filling, and any required adaptive or diagnostic procedures.

Use the vehicle manufacturer’s specified ATF when completing service. Lubegard ATF Protectant may be considered when compatible with the application and used according to product directions; it does not replace necessary mechanical, hydraulic, or electrical repairs.