Lincoln Corsair: Automatic Transmission - 8-Speed Automatic Transmission – 8F35/8F40 / Diagnosis and Testing - Road Testing Vehicle

Shift Point Road Test

NOTE: Always drive the vehicle in a safe manner according to driving conditions and obey all traffic laws.

Upshift Gear Sequence

At times the 8-speed transmission may skip gears when the vehicle starts from a complete stop. This is normal and desired behavior. This transmission may also be described as a 7-speed transmission. For the 7-speed applications, 2nd gear is not utilized.

At part pedal when acceleration is brisk, single step upshifts would result in very frequent shift events (very short time in gear). Double step upshifts results when a longer time is spent in gear.

However, at light pedal or road load, single step upshifts will occur. The small 8-speed gear steps allow the engine speed to drop to lower values than it would in the 6-speed transmission; providing for the best fuel economy. In contrast, when the 8-speed transmission is at heavy or max pedal, the small steps keep the engine closer to the horsepower peak for best performance.

Downshift Gear Sequence

At times the 8-speed transmission may skip gears when the vehicle downshifts to a complete stop. This is normal and desired behavior. This transmission may also be described as a 7-speed transmission. For the 7-speed applications, 2nd gear is not utilized.

The same skip shift strategy that is used for the upshift may be applied during downshift.

Most performance based automatic transmission DTC s require the fault to be detected consecutively multiple times (up to 5 times) before setting a DTC . Performing the shift point road test as detailed below increases the likelihood that a DTC sets if a fault is present in the system.

Shift Point Road Test

1. Bring the engine and transmission up to normal operating temperature.
   

1. Operate the vehicle with the selector lever in the D position.
   

1. From a stop, accelerate the vehicle to 80 km/h (50 mph) with the shifts occurring at approximately 2,000 rpm. Stay in 8th gear for 30 seconds or until the TCC applies. Repeat this two times.
   

1. From a stop, accelerate the vehicle to 80 km/h (50 mph) with the shifts occurring at approximately 3,000 rpm. Stay in 8th gear for 30 seconds or until the TCC applies. Repeat this two times.
   

1. If the transmission fails to upshift/downshift,
   REFER to: Diagnosis By Symptom (307-01A Automatic Transmission - 8-Speed Automatic Transmission – 8F35/8F40, Diagnosis and Testing).

  Shift Speed Chart