HARSH SHIFT CONDITIONS AND ON CAR SERVICE INFORMATION
MODELS AFFECTED: 1985-1987 DE VILLES AND FLEETWOODS 1986 ELDORADOS AND SEVILLES
This bulletin supplements information previously published in Serviceman Bulletins T-87-43, T-87-44 and T-87-52.
Some 1985-1987 De Villes and Fleetwoods, and 1986 Eldorados and Sevilles equipped with THM 440-T4 transaxles may exhibit very harsh, or intermittent harsh 3-2 down shifts. Very harsh 3-2 part throttle down shifts between 20-40 mph may be caused by a missing or mislocated #2 (3-2 control) checkball. An intermittent harsh 3-2 down shifts during a part throttle detent down shift may be caused by a broken 3-2 line control retainer.
VERY HARSH, PART THROTTLE 3-2 DOWN SHIFTS BETWEEN 20-40 MPH
To repair this condition, remove the valve body and inspect for the checkball. A mislocated checkball may have bent the spacer plate, in which case the spacer plate must be replaced (see Figure 1).
INTERMITTENT HARSH 3-2 DETENT DOWN SHIFT
To repair this condition, remove the transaxle side cover and replace the broken retainer (see Figure 2).
Part Number Description
8658678 Retainer, 3-2 Line Control
For warranty purposes, use Labor Operation:
K 6570 4.8 hrs. Check Ball Missing or Mislocated (Includes replacement of 3-2 line control retainer if required)
T6258 2.9 hrs. (C-car) Retainer, 3-2 Line Control 3.2 hrs. (E/K)
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
