Automatic Transmission - 4L80-E - Overhaul & Testing: Other Chevrolet Silverado 2500

GEAR RATIOS

TRANSMISSION GEAR RATIOS

CASE EXTENSION & SPEED SENSORS

Thoroughly clean transmission exterior. Drain fluid and remove torque converter. Place transmission in holding fixture. Using slide hammer, remove slip yoke seal. Remove case extension bolts, case extension and seal. Remove case extension bearing assembly (some models). Remove input speed sensor and output speed sensor (output speed sensor plug on 4WD models). (Scheme 58)

Scheme 58

END PLAY CHECKS

1. Using dial indicator, check front and rear unit end play. (Scheme 59)and (Scheme 60). Press down on turbine shaft and then pull up on turbine shaft to eliminate any clearance between overdrive carrier and snap ring. Pull up on turbine shaft while holding output carrier upward with screwdriver to measure front unit end play. Front unit end play should be.004-.022" (.10-.56 mm).
2. Push in on output shaft to take up any slack. Move output shaft inward and outward to measure rear unit end play. Rear unit end play should be.005-.025" (.13-.64 mm). Record measurements for reassembly reference.

Scheme 59

Scheme 60

FORWARD & DIRECT CLUTCH

Using Clutch Remover/Installer (J-38358-A), remove forward clutch assembly. (Scheme 67) Using Clutch Remover/Installer (J-38733), remove direct clutch assembly. (Scheme 66)

MANUAL 2-1 BAND & INTERMEDIATE CLUTCH

Note. Manual 2-1 band may also be referred to as front band.

Remove manual 2-1 band. Remove snap ring, backing plate and intermediate clutch plates. Remove intermediate clutch wave plate. (Scheme 65)

CENTER SUPPORT, REAR GEAR UNIT & LOW-REVERSE BAND

Note. low-reverse band may also be referred to as rear band.

1. Remove center support bolt and discard. (Scheme 64) Remove snap ring. Using Gear Assembly Remover/Installer (J-38868), Adapter (J-21364-A) and slide hammer handle, remove gear assembly. (Scheme 63)
2. Remove low-reverse band and thrust washer. (Scheme 61) If necessary, select proper selective thrust washer based on end play measurements. See «END PLAY CHECKS»(ref-130161-S10749298272001112800000). Set thrust washer aside for reassembly.
3. Remove output shaft seal snap ring. Using slide hammer, remove output shaft seal.

TRANSMISSION CASE

Note. Always use manufacturer-recommended transmission fluid during cleaning or reassembly of transmission components. See LUBRICATION in appropriate SERVICING article. Use petroleum jelly to hold bearings and spacers in position.

Center Support Recondition Procedure

If Bore Gauge (J-39919-2) fits into center support bolt hole, replace center support and bolt in order to avoid component damage. To determine if center support has not been previously reconditioned, insert bore gauge into center support bolt hole. If gauge does not fit, using Thread Reamer (J-39919-1), ream center support bolt hole to fit NEW service bolt. see scheme 30

MANUAL 2-1 & LOW-REVERSE SERVOS

Note. Manual 2-1 and low-reverse servos may also be referred to as front and rear servos.

CENTER SUPPORT & REAR GEAR UNIT

Note. Low-reverse band may also be referred to as rear band.

1. Install low-reverse band and thrust washer. Ensure band anchor pins engage band, and band assembly stop is in place. Install appropriate selective thrust washer. (Scheme 61)
2. Install center support spacer into groove above low-reverse band. Ensure spacer opening is place at the 9 o'clock position. (Scheme 62) Using Gear Assembly Remover/Installer (J-38868), Adapter (J-21364-A) and slide hammer handle, install gear assembly. (Scheme 63)
3. Install upper center support snap ring with beveled edge side up and opening at the 9 o'clock position. Using dial indicator, check rear unit end play. (Scheme 60) Rear unit end play should be.005-.025" (.13-.64 mm).
4. If rear unit end play is not correct, select proper size thrust washer. See «REAR END PLAY THRUST WASHER IDENTIFICATION»(ref-130161-S30935020632001112800000) table. If necessary, remove center support and rear unit to change selective thrust washer.
5. Using Center Support Aligner (J-23093), push center support splines counterclockwise against case splines (away from rear servo). Align center support with bolt hole. Using NEW bolt, install center support bolt. (Scheme 64) Tighten bolt to 32 ft. lbs. (43 N.m). Install rear oil cooler pipe fitting with NEW seal and tighten to 26 ft. lbs. (35 N.m).

REAR END PLAY THRUST WASHER IDENTIFICATION

Scheme 61

Scheme 62

Scheme 63

Scheme 64

INTERMEDIATE CLUTCH

1. Install intermediate wave plate with tangs facing downward. Install intermediate clutch plates, starting with steel plate, and then alternating with composition plate (4 steel and 4 composition). (Scheme 65) Install backing plate with flat side down. Install snap ring at the 9 o'clock position.
2. Using feeler gauge, ensure clearance between clutch plates and backing plate is.040-.107" (1.02-2.72 mm). Install manual 2-1 band into case and ensure proper alignment with anchor pin. Using Clutch Plate Aligner (J-24396), align intermediate clutch assembly.

Scheme 65

Apply air pressure into center support hole to hold intermediate clutch plates in place. Using Clutch Installer (J-38733), install direct clutch assembly. (Scheme 66) Using Clutch Installer (J-38358-A), install forward clutch assembly and thrust bearing. (Scheme 67)and (Scheme 71).

Note. Check installed height of speed sensor ring (on forward clutch housing). Top of speed sensor ring to oil pump gasket surface height should be 3.85-3.89" (98.0-99.0 mm).

Scheme 66

Scheme 67

SPEED SENSORS & CASE EXTENSION

Install and secure torque converter. Install case extension. Install speed sensors. (Scheme 58)

Scheme 68

Scheme 69

Scheme 70

Scheme 71

Scheme 72

Scheme 73