3-2 DOWNSHIFT BUMP 440T4 TRANSAXLE,NEW P/N

Model and Year 1984-85 THM 440-T4 TRANSAXLES MODELS CP-1985 & CM-1985 1/2

TO: ALL CHEVROLET DEALERS

Some 1985 THM 440-T4 "CM" & "CP" model transaxles (refer to figure 1), may exhibit a 3-2 downshift bump. This condition may be most prevalent during a part-throttle downshift with the air conditioner operating. A slight transaxle tie-up condition which shakes or rattles the instrument panel during the downshift may also be experienced.

When servicing any 1985 THM 440-T4 "CM" & "CP" model for a 3-2 downshift bump, order and install service package part number 8646951.

Service package part number 8646951 contains one each of the following:

3-2 Control Valve Spring 1-2 Servo Boost Valve Instruction Sheet

Refer to Figure 2 of this bulletin and the appropriate Service Information Manual for proper installation procedures. Models "CP" are 1985 models while "CM" is a 19851/2 model. There are differences between the 1985 and 1985 1/2 models which are explained in Chevrolet Dealer Service Bulletin 85-86, published May, 1985.

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.