ON VEHICLE SEDIMENT INSPECTION 4T80-E (INFORMATION

SUBJECT: ON-VEHICLE SEDIMENT INSPECTION (INFORMATION)

VEHICLES AFFECTED: 1993 "V" MODEL

APPLICATIONS:

------------ 1993 Cadillac Allante (V-Car) with Hydra-Matic 4T80E (MH1) transaxle, Model 2AJN.

BULLETIN COVERS:

NOTE: The following information contained in this Service Bulletin applies to the 4T80-E transaxle only and should not be referenced when performing service to any other HYDRA-MATIC transmission.

Whenever it is necessary to remove the bottom pan on any Hydra-matic 4T80-E transaxle for fluid servicing and/or on-vehicle service, you may notice some amount of debris located in the Scavenger screens, on the bottom pan and magnet. This is because:

1. The suction and fluid flow characteristics of the 4T80-E combined with the visible external scavenger screens allow sediment to be seen. In other Hydra-matic transmissions, this sediment would be contained in the self-contained (traditional) bottom pan filter.

2. The 4T80-E is "final tested" with the side cover and bottom pan assembled to the unit. Traditionally, transmissions are tested with these pan(s) off and some of this sediment would have been flushed out of the transmission.

This visible sediment may be composed of:

o Metal slivers and very small pieces of aluminum

o Fiber clutch plate 'hairs'

o Case cover seal material which may appear orange in colour

This amount of sediment is inherent to the 4T80-E transaxle and does not indicate evidence of internal component failure which would require a transaxle replacement (SRTA) or unit overhaul.

Debris found in the above mentioned components which may indicate internal transaxle concerns are:

o Excessive fiber clutch plate material (large sections of paper)

o Bushing material (bronze or brown colored)

o Large chunks of steel or aluminum

o 0-ring or Teflon seal material

Upon reinstallation of the bottom pan thoroughly clean the bottom pan, magnet and install new scavenger screens and bottom pan gasket.

SERVICE MANUAL INFORMATION:

Whenever performing any on-vehicle service to the 4T80-E transaxle, always refer to the On-Vehicle Repair Section of your Service Manual and instruction sheets contained in service parts packages.

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.