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Automatic Transmission - Diagnosis - 4L80-E: Application GMC Pickup C2500

Automatic Trans 1 illustration ~150 words

APPLICATION

ApplicationEngine
Chevrolet: "C", "G", "K", "P", "R", "V" Series4.3L, 5.7L, 6.2L & 7.4L
GMC: "C", "G", "K", "R", "V" Series4.3L, 5.7L, 6.2L & 7.4L

THM 4L80-E APPLICATION

CLUTCH & BAND APPLICATION CHART

Selector PositionSolenoidElements In Use
"D" (Overdrive)
1st Gear"A" ON/"B" OFF(1) Overdrive Roller Clutch, Forward Clutch, (2) Intermediate Sprag Clutch & Low Roller Clutch
2nd Gear"A" OFF/"B" OFF(1) Overdrive Roller Clutch, Forward Clutch, (1) Intermediate Sprag Clutch, Intermediate Clutch & (3) Low Roller Clutch
3rd Gear"A" OFF/"B" ON(1) Overdrive Roller Clutch, Forward Clutch, Direct Clutch, (3) Intermediate Sprag Clutch, Intermediate Clutch & (3) Low Roller Clutch
Overdrive"A" ON/"B" ON4th Clutch, (3) Overdrive Roller Clutch, Forward Clutch, Direct Clutch, (3) Intermediate Sprag Clutch, Intermediate Clutch & (3) Low Roller Clutch
"D" (Manual 3rd)
1st Gear"A" ON/"B" OFFOverrun Clutch, (1) Overdrive Roller Clutch, Forward Clutch, (2) Intermediate Sprag Clutch & (1) Low Roller Clutch
2nd Gear"A" OFF/"B" OFFOverrun Clutch, (1) Overdrive Roller Clutch, Forward Clutch, (1) Intermediate Sprag Clutch, Intermediate Clutch & (3) Low Roller Clutch
3rd Gear"A" ON/"B" OFFOverrun Clutch, (1) Overdrive Roller Clutch, Forward Clutch, Direct Clutch, (3) Intermediate Sprag Clutch, Intermediate Clutch & (3) Low Roller Clutch
"2" (Manual 2nd)
1st Gear"A" ON/"B" OFFOverrun Clutch, (1) Overdrive Roller Clutch, Forward Clutch, (2) Intermediate Sprag Clutch & (1) Low Roller Clutch
2nd Gear"A" OFF/"B" OFFOverrun Clutch, (1) Overdrive Roller Clutch, Forward Clutch, Front Band, (3) Intermediate Sprag Clutch, Intermediate Clutch & (3) Low Roller Clutch
"1" (Manual Low)
1st Gear"A" ON/"B" OFFOverrun Clutch, (1) Overdrive Roller Clutch, Forward Clutch, (2) Intermediate Sprag Clutch, (1) Low Roller Clutch & Rear Band
2nd Gear"A" OFF/"B" OFFOverrun Clutch, (1) Overdrive Roller Clutch, Forward Clutch, Front Band, (3) Intermediate Sprag Clutch, Intermediate Clutch & (3) Low Roller Clutch
"R" (Reverse)"A" ON/"B" OFF(1) Overdrive Roller Clutch, Direct Clutch & Rear Band
"N" Or "P""A" ON/"B" OFF(1) Overdrive Roller Clutch, All Other Clutches & Bands Released Or Ineffective
(1) Holding. (2) Applied but not effective. (3) Overrunning.
(1)Holding.
(2)Applied but not effective.
(3)Overrunning.

CLUTCH & BAND APPLICATION CHART

Scheme 489

Scheme 489: OUTPUT SPEED SENSOR CIRCUIT (1991 2WD - EXCEPT "C" & "K" SERIES)
Scheme 489: OUTPUT SPEED SENSOR CIRCUIT (1991 2WD - EXCEPT "C" & "K" SERIES)

The speed sensor, which is a Permanent Magnet (PM) generator, provides Digital Ratio Adapter Control (DRAC) with vehicle speed information. PM generator, mounted in transmission, produces a pulsing voltage signal whenever the vehicle speed is more than 3 MPH. Voltage level and pulse increase with vehicle speed. DRAC converts this signal to a pulsing signal by grounding circuit 437 (Brown wire) 2000 times per mile. Control module uses this signal in calculations to determine vehicle adjustments.

Note. Test numbers refer to numbers on diagnostic chart.

  1. This step tests for voltage variation while wheels are turning. Voltage will be low at low wheel speeds (4-6 volts at 20 MPH).
  2. This step checks if vehicle speed sensor signal is present at DRAC.
  3. This step checks output speed sensor signal.

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