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HOMESERVICE MANUALSGMC1999FORWARD CONTROL 5.7 R, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 119 (AUTOMATIC TRANSMISSION SERVICING)LUBRICATIONDRAINING & REFILLING
1999 GMC Forward Control 5.7 R, Automatic

Draining & Refilling

1999 GMC Forward Control 5.7 R, AutomaticSECTION Draining & Refilling
WARNING: This page is about a different car, the 2003 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.
WARNING: When the transmission is at operating temperatures, take necessary precautions when removing the check/fill plug, to avoid being burned by draining fluid.
  1. Raise and suitably support the vehicle. Place a drain pan under the transmission. Clean any dirt from around the transmission check/fill plug. Remove the transmission fluid check/fill plug and allow the fluid to drain. See Fig 1 .
  2. Support the transmission oil pan. Remove the transmission oil pan bolts. Loosely reinstall the fluid check/fill plug. Lightly tap the oil pan with a rubber mallet or pry gently in order to loosen the pan. Remove the transmission oil pan. See Fig 2 . Drain the remaining fluid from the oil pan.
    NOTE: Observe position of the filter before removal to aid in installation.
  3. Grasp firmly while pulling down with a twisting motion in order to remove the filter. Remove the filter seal. The filter seal may be stuck in the pump. If necessary, carefully use pliers or another suitable tool to remove the seal. Discard the seal. See Fig 3 and Fig 4 .
  4. Inspect the transmission fluid. See CHECKING FLUID LEVELS  . Inspect the transmission fluid filter. Pry the metal crimping away from the top of the filter and pull apart. The filter may contain evidence for root cause diagnosis:
    • Clutch material.
    • Bronze slivers indicating bushing wear.
    • Steel particles.
    NOTE: Remove ALL traces of old gasket material from the transmission case and the oil pan gasket surfaces.
  5. Clean the oil pan gasket mating surfaces, on both the transmission case and the transmission oil pan, with solvent and air dry. Coat the new filter seal with a small amount of Transjel(tm) (J 36850) or equivalent. Install the new filter seal into the transmission case. Gently tap the seal into place using a suitable size socket. See Fig 5 .
  6. Install the new oil filter into position as noted during removal. Inspect the oil pan bolts and washers to determine if the conical washers are reversed. Reuse the oil pan bolts and washers if the conical washers are NOT reversed. Replace the oil pan bolts and washers if the conical washers are reversed. See Fig 6 .
  7. Install the new oil pan gasket to the oil pan sealing surface. Position the oil pan to the transmission case and support the oil pan.
  8. Install the oil pan bolts. Tighten the transmission oil pan bolts alternately and evenly to specification. See TORQUE SPECIFICATIONS  . Remove the transmission fluid check/fill plug. Fill the transmission with appropriate fluid through the check/fill plug hole until fluid begins to pour out, then install the check/fill plug hand-tight. See RECOMMENDED FLUIDS  .
  9. Complete filling the transmission with fluid to the proper level. See CHECKING FLUID LEVELS  . Tighten the transmission fluid check/fill plug to specification. See TORQUE SPECIFICATIONS  . Inspect the oil pan gasket for leaks.
Fig 1: Locating Transmission Fluid Check/Fill Plug
G00056977Courtesy of GENERAL MOTORS CORP.
RENDER: 1.0x

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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.