SLIP OR NO DRIVE RESULTING FROM LOW LINE PRESSURE

MODELS AFFECTED: 1987 DE VILLE, ELDORADO AND SEVILLE

Some 1987 440-T4 transaxles built between November 26, 1986 (Julian Date 330) and January 12, 1987 (Julian Date 012), may exhibit a slip or no drive condition as a result of low line pressure.

This condition may be caused by the pump slide binding on excessive casting flash when the slide is in the tow pressure position.

To verify the possibility of a binding pump slide, check line pressure while the vacuum signal line is removed and reinstalled on the modulator fitting. If normal (minimum/maximum) pressures are recorded, proceed with the usual diagnostic steps for the cause of low line pressure.

If pressures do not vary with vacuum signal changes, inspect for pump slide bind by removing the oil pump cover and rotating the slide by hand. If present, excessive flash will cause the slide to bind. If found, replace the oil pump assembly.

Refer to the appropriate Service Information Manual index for oil pump replacement procedures.

For warranty purposes, use K6570 for 3.3 hours on De Ville/Fleetwood and 3.8 hours on Eldorado and Seville.

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.