Automatic Transmission - Servicing - Except Allison: Other Chevrolet Silverado 2500

Transfer Case

Check transfer case fluid level at each engine oil change. Under normal driving conditions, change transmission fluid every 50,000 miles.

Manufacturer recommends Dexron-III ATF for NV149, NV261C and NV263C. Manufacturer recommends Auto-Trak II Fluid (GM P/N 12378508) for NV246 and NV246C.

The following refill capacities given are approximate. Correct fluid level should always be determined by marks on dipstick, rather than amount of fluid added. DO NOT overfill. See TRANSMISSION FLUID CAPACITIES table.

TRANSMISSION FLUID CAPACITIES

The following refill capacities given are approximate. Correct fluid level should always be determined by level of fluid at fill hole, rather than amount of fluid added. DO NOT overfill. See TRANSFER CASE FLUID CAPACITIES table.

TRANSFER CASE FLUID CAPACITIES

Preparation

1. After the repair or replacement transmission is installed in the vehicle, do not reconnect the oil cooler pipes.
2. Remove the fill cap (9) on the Transmission Oil Cooler and Line Flusher (J-35944-A) and fill the flusher tank (4) with 20-21 oz. (0.6L) of flushing solution using the measuring cup (6). DO NOT overfill. Install the fill cap (9) on the flusher and pressurize the flusher tank (4) to 80-100 psi (550-700 kPa), using the shop air supply at the tank air valve (9). (Scheme 445)
3. Connect the flusher discharge hose (5) to the oil cooler return pipe (top connector) (may require J-35944-600). Clip the discharge hose (5) onto the oil drain container. Attach the flusher to the undercarriage of the vehicle with the hook provided, and connect the flushing system feed supply hose (3) from the flusher to the oil cooler feed pipe (bottom connector) (may require J-35944-600). (Scheme 446)
4. With the water supply valve (1) on the flusher in the OFF position, connect the water supply hose (7) from the flusher to the water supply at the faucet. (Scheme 445)and (Scheme 446). Turn ON the water supply at the faucet.

Scheme 445

Scheme 446

TRANSMISSION & OIL COOLER FLOW CHECK

1. Disconnect both hoses from the oil cooler pipes. Connect the oil cooler feed pipe (bottom connector) to the transmission and the return pipe (top connector) (may require J-35944-600) to the discharge hose (5). Clip the discharge hose (5) onto the empty oil drain container. see scheme 8
2. Confirm the transmission is filled with ATF. See «CHECKING FLUID LEVEL & CONDITION (4L60-E)»(ref-138559-S14689602832002041700000) or «CHECKING FLUID LEVEL & CONDITION (4L80-E)»(ref-138559-S03212473452002041700000). Start the engine with the transmission in Park range and run for 30 seconds. A minimum of 2 qts. (1.9L) must be discharged during this 30 second run time. If fluid flow is greater than 2 qts. (1.9L) in 30 seconds, go to next step. If fluid flow is less than 2 qts. (1.9L) in 30 seconds, perform the following diagnosis: Disconnect the oil cooler feed line at the radiator. Connect the discharge hose (5) to the cooler feed line. Clip the discharge hose (5) to the empty oil drain container. see scheme 8 Start the engine with the transmission in PARK range and run for 30 seconds. A minimum of 2 qts. (1.9L) must be discharged during this 30 second run time. Perform the following according to the flow rate: Insufficient feed flow: Inspect the transmission. Sufficient feed flow: Inspect the oil cooler return pipe and the oil cooler (and auxiliary cooler, if equipped).
3. Remove the discharge hose (5), reconnect the cooler feed and return pipes to the transmission and refill the unit to the proper fluid level. Inspect the transmission oil cooler pipe connections at the radiator, the auxiliary cooler (if equipped) and the transmission for leaks.

ON-VEHICLE REPAIRS

Various components may be serviced without transmission removal, depending on application. For servicing of these components, see appropriate component under ADJUSTMENTS and/or REMOVAL & INSTALLATION . For additional information on testing electrical components, see appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.

PARK/NEUTRAL POSITION SWITCH

With an assistant in driver's seat, raise and support vehicle. The transmission must be in the PARK or NEUTRAL positions only. Loosen the Park/Neutral Position (PNP) switch retaining bolts and rotate the switch slightly, while assistant attempts to start engine. After engine starts, turn engine off. Tighten PNP switch bolts to specification. See TORQUE SPECIFICATIONS . Ensure vehicle does not start in any range other than Park and Neutral.

SHIFT CABLE

1. Ensure the gearshift lever and the transmission manual shaft lever are in the Park position. Raise and support the vehicle. Pull back the White plastic cover (1) on the center connector. (Scheme 447)
2. Pull up on the center tabs of the lock button (2). (Scheme 448) NOTE: This step must be performed correctly to avoid a misadjusted cable. Do not grasp the shift cable end (2) during this procedure.
3. Release the shift cable end (2) and allow the blue spring to tension/adjust the shift cable system. (Scheme 449) Pull the White cover (3) on the shift cable end (1) back.
4. Push the Natural colored lock button (2) down to engage the locking teeth on the shift cable end (1). (Scheme 450) Release the White cover (1). (Scheme 451)
5. Verify the White cover (1) conceals the Natural colored lock (2). (Scheme 452) If the White cover (1) does not conceal the Natural colored lock (2), the shift cable must be readjusted.
6. Test the transmission for proper shift operation. If all of the gear positions cannot be achieved, the shift cable must be readjusted.

Scheme 447

Scheme 448

Scheme 449

Scheme 450

Scheme 451

Scheme 452

CONTROL & SHIFT SOLENOIDS (4L60-E)

Note. Valve body removal is not necessary for the following procedure.

EXTENSION HOUSING REAR OIL SEAL (4L60-E)

Note. Tools required: Rear Extension Seal Installer (J-21426), and Transmission Assembly Lubricant (J-36850).

Note. Tools required: Park/Neutral Position Switch Adjustment Tool (J-41364-A).

Checking Procedure

Note. Tools required: Gauge Pin (J-21370-10), and Band Apply Pin Checking Tool (J-38737).

1. Place the rear servo pin gauge in the servo bore. (Scheme 453)
2. Position the band apply pin checking tool over the bore with the hex nut facing the parking pawl linkage. Tighten the band apply pin checking tool with the 2 rear servo cover bolts to 18 ft lbs. (24 N.m). (Scheme 454)
3. Ensure the gage pin moves freely in the tool and the pin bore.
4. In order to determine the correct pin length, tighten the nut on the gauge to 25 ft lbs. (34 N.m). Select the correct band apply pin length. (Scheme 455)

Scheme 453

Scheme 454

Scheme 455

SHIFT CABLE (COLUMN END)

Note. The range selector cable is a 2 piece cable assembly. The front half (column end) or rear half (transmission end) of the range selector cable can be removed without removing the other end/half of the range selector cable assembly.

SHIFT CABLE (TRANSMISSION END)

Note. The range selector cable is a 2 piece cable assembly. The front half (column end) or rear half (transmission end) of the range selector cable can be removed without removing the other end/half of the range selector cable assembly.

VALVE BODY & PRESSURE SWITCH (4L80-E)

Note. Tools required: Transmission Assembly Lubricant (J-36850).

2-4 SERVO (4L60-E)

Note. Tools required: Servo Cover Depressor (J-29714-A).