BINDING OR INOPER. IN REVERSE STUCK 4-3 SEQ. VALVE/2-3 SHIFT

MODELS AFFECTED: 1990 BROUGHAM WITH HYDRA-MATIC 4L60 TRANSMISSION (ENGINE VIN CODE 7)

This bulletin is being revised to include the Cadillac Brougham. Some 1990 Broughams with the Hydra-Matic 4L60 (THM 700-R4) transmission may experience a binding or inoperative condition when placed in the reverse range. The car may feel as though the engine is being "brake torqued" when in the reverse range with no movement.

This condition may be caused by the 4-3 sequence valve and/or the 2-3 shift valve stuck in the upshifted position in the transmission valve body. Refer to Figure 1.

To repair this condition the valve body must be completely disassembled and reconditioned and the transmission cooler and cooler lines should be flushed according to the procedures contained in the 4L60 unit repair section of the Service Information Manual.

IMPORTANT: Over torquing the bolts during unit reassembly may cause valves to bind. The correct bolt torque for the Hydra-Matic 4L60 control valve assembly is 8-14 N-m (6-10 ft.lb.). Torquing bolts to the minimum specification is recommended.

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.