For 1990-2009 cars

# SERVICE MANUAL UPDATE FLUID FLOW CIRCUITS CORRECTED

TRANSMISSION APPLICATIONS: SUBJECT: ------------------------- ------- 1987 THM 440-T4 (ME9) 1987 SERVICE MANUAL UPDATE OF FLUID FLOW DIAGRAMS

TRANSMISSION MODELS: VEHICLE APPLICATIONS: ------------------ -------------------- ALL A, C, E, H, K CARS

BULLETIN COVERS: (Figure 1) ---------------- Fluid flow diagrams published in the 440-T4 Hydraulic Diagnosis section of the 1987 Oldsmobile Service Manual were not current. Use the corrected diagram in this bulletin to update your service manual. Note the following two changes:

o Spacer plate hole for the Number 14 checkball was added, making the checkball functional (Refer to arrow, Figure 1). With this change, line pressure is now boosted by detent fluid at full throttle opening.

o Modulator circuit no longer feeds the 3-2 coastdown valve directly, and 1-2 servo release circuit was routed to the 3-2 coastdown valve by a crossover pipe between the pump cover and the control valve assembly (Refer to dotted line and circle, Figure 1). These changes were part of a package to improve 3-2 shift feel.

#### SERVICE NOTES:

The spacer plate and checkball location illustrations in the 1987 Service Manual are correct.

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.