WORKHORSE CUSTOM CHASSIS
Service Manual
2007 W Series
SECTION
7.2
PAGE
456
Automatic Transmission – Allison
2007 W Series Chassis
© 2006 Workhorse Custom Chassis — All Rights Reserved
WSM082106
C. Pause 2 to 3 seconds in each range.
D. Return the shift selector to PARK.
E.
Verify that all of the selector positions match the
scan tool display.
8. Inspect the throttle angle input.
A.
Apply the brake pedal and ensure the parking brake
is set.
B. Ensure the shift selector is in PARK.
C.
Monitor the throttle angle while increasing and
decreasing the engine speed with the throttle pedal.
The scan tool throttle angle should increase and
decrease with the engine speed.
If any of the above checks do not perform properly,
record the result for reference after the completion of the
Road Test Procedure.
Upshift Control and Torque Converter Clutch (TCC) Apply
The transmission control module (TCM) calculates
the upshift points based on the throttle angle and the
engine, turbine and output speed. When the TCM
determines that conditions are met for a shift to occur,
the TCM commands the shift, and controls A and B
solenoid current to proper control clutch pressures
during the shift.
Perform the following steps:
1. Choose a throttle position of 10 percent, 25 percent or
50 percent. All throttle angles shown should be tested
to cover the normal driving range.
2. Monitor the following scan tool parameters:
• Throttle angle
• Vehicle speed
• Engine speed
• Output shaft speed
• Commanded range
• Slip speed
• Solenoid states
3. Place the shift selector in DRIVE.
4. Using the chosen throttle angle, accelerate the
vehicle. Hold the throttle steady.
5. As the transmission upshifts, note the vehicle speed
when the shift occurs for each range change. There
should be a noticeable shift feel or engine speed
change within 1 to 2 seconds of the commanded range
change.
6. Shift speeds may vary slightly due to transmission fl uid
temperature or hydraulic delays in responding to the
electronic controls.
• Note any harsh, soft or delayed shifts or slipping.
• Note any noise or vibration.
7. Repeat steps 1-6 to complete all throttle angles.
IMPORTANT:
The TCC will not engage until the engine is in closed
The TCC will not engage until the engine is in closed
loop operation. The vehicle must be in a near cruise
loop operation. The vehicle must be in a near cruise
condition, not accelerating or coasting, and on a level
condition, not accelerating or coasting, and on a level
road surface.
road surface.
Inspect for TCC apply in SECOND, THIRD, FOURTH
and FIFTH range.
• Note the TCC apply point. When the TCC applies there
should be a noticeable drop in engine speed and a drop
