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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different car >> Section 56 (Automatic Transmission - 6L90 (MYD) - Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> No First, Second, Third, and Fourth Gear

No First, Second, Third, and Fourth Gear

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
Checks Causes
A/Trans Fluid Pan Assembly (29) Verify proper fluid level and condition, inspect transmission assembly for leaks.
Control Valve Upper Body Assembly (304) Inspect for sticking, damaged, or worn 1-2-3-4 clutch regulator valve (337) and spring (326).
Control Solenoid (w/Body and TCM) Valve Assembly (314)
1-2-3-4 and 3-5-R Clutch Assembly (51)
  • Inspect clutch pack retaining ring (429) for proper installation. If the retaining ring is out of the groove the following parts must be replaced: 1-2-3-4 and 3-5-R clutch housing (427), 1-2-3-4 and 3-5-R clutch bearing assembly (428) and the 1-2-3-4 clutch backing plate retaining ring.
  • Inspect for a cracked or damaged 1-2-3-4 clutch piston (414), piston housing (417), spring (413), and dam assembly (412).
  • Inspect for cut, worn, or damaged 1-2-3-4 clutch piston seal (416), inner seal (423), and housing seals (424 and 425).
  • Inspect for improper selective 1-2-3-4 clutch backing plate retaining ring (429).
Fluid Filter Assembly (26)
  • Inspect for damaged or restricted fluid filter assembly (26).
  • Inspect for damaged fluid filter seal assembly (25) or improper sealing interface, leaks, and fluid aeration.
Torque Converter (with Fluid Pump) Housing Assembly (2) Inspect for damaged or scored pump housing (203), cover (219), rotor (217), slide (212) and vanes (216).
Torque Converter (with Fluid Pump) Housing Assembly (2) Inspect for damaged or leaking 1-2-3-4 and 3-5-R clutch fluid seal rings (230).
Center (w/2-6 Low and Reverse Clutch) Support Assembly (67) Inspect for worn or damaged low clutch sprag assembly (467).
A/Trans Fluid Pump (Transfer) Seal Assembly (19) Inspect for damage or leaks.
1-2-3-4 Clutch (with Output Carrier Inner Sun Gear Shaft) Hub Assembly (61) Inspect for damaged splines on the hub assembly.