GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1999 🢒 GMC MD Steel Tilt (W Model) 🢒 Transmission/Transaxle 🢒 Automatic Transmission - 4L80-E 🢒 Harsh Shift D4 to D3, D2, or D1

Harsh Shifts -- Fourth to Third, Second, or First

Checks

Cause

Spring Assembly (506)

Not functioning

Checkball

Plugged

Snap Ring (511)

Not seated