HARSH UPSHIFTS/3-2 SHIFTS SERVICE INFORMATION (440-T4). Chevrolet Celebrity 1985

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# HARSH UPSHIFTS/3-2 SHIFTS SERVICE INFORMATION (440-T4)

#### MODEL AND YEAR: 1984-86 CELEBRITY WITH 440T4 TRANSMISSION

Bulletin 86-190 (Section 7A) dated Nov., 1986 is being reissued to correct the Service Package P/N listed for Harsh Upshifts At High Altitude. All copies of 86-190 should be destroyed.

#### HARSH UPSHIFTS AT HIGH ALTITUDE 1985-1986 MODELS

Harsh upshifts at high altitudes may be caused by high line pressure due to low engine vacuum and may be corrected on certain transaxle models by installing an aneroid modulator service package.

The service package includes a new vacuum modulator assembly, modulator valve, O-ring seal, and instruction sheet.

SERVICE PACKAGE P/N TRANSAXLE MODEL IDENTIFICATION ------------------- ------------------------------ (Refer to Figure 1)

1985 1986 ---- ---- 5CM 6CFH 8646956 5CN 6CMH 5CP 6CNH 5CW 5HA

A new engine to modulator vacuum line P/N 14062624 must also be installed.

#### HARSH 3-2 DOWNSHIFT AT HIGH ALTITUDE 1984-1986 MODELS

A harsh 3-2 downshift at high altitude may be corrected by installing new spacer plate gaskets and a 3-2 control valve spring. These parts, including instructions are contained in a service package.

3-2 CONTROL VALVE TRANSAXLE MODEL IDENTIFICATION SPRING PACKAGE P/N (Refer to Figure 1) ------------------ ------------------------------ 1985 1986 ---- ---- 5CM 6CMH 8646983 5CN 6CNH 6CFH

8646993 5CP 5CW

#### NOTE: Before installing a service replacement transmission assembly (SRTA) that will be used extensively at high altitude, install the new 3-2 control valve spring. (Designated high altitude counties listed on pages 3 and 4 of this bulletin.)

#### HARSH 3-2 SHIFT MANEUVER (17 TO 20 MPH) AT ANY ALTITUDE

Commencing with the start of production 1987, an orifice pipe has been added between the 1-2 servo release cover plate and the 3-2 coastdown valve to allow for a smoother second gear apply. The four new parts installed as a set will service certain past model transaxles and may correct a harsh 3-2 shift maneuver.

P/N DESCRIPTION TRANSAXLE MODEL IDENTIFICATION --- ----------- ------------------------------ (Refer to Figure 1)

1985 1986 8662322 Body Assembly ---- ---- Oil Pump Complete 5CM 6CFH 5CN 6CMH 5CP 6CNH 5CW

8662376 Gasket, Release All Models Listed Cover

8662377 Pipe, Plug and All Models Listed Release Cover Assembly

8662394 Clip, Conduit All Models Listed

#### NOTE: If the new pump body assembly has a 1-pin 3rd clutch switch, remove it and replace with the 2-pin switch from the original pump body assembly.

#### DESIGNATED HIGH ALTITUDE COUNTIES*

STATE OF ARIZONA STATE OF NEVADA Apache Carson City Humboldt Navajo Douglas Lander Elko Lyon Esmeralda Mineral STATE OF COLORADO Eureka Storey Adams Jefferson White Pine Alamosa Lake Arapahoe La Plata Archuleta Larimer STATE OF NEW MEXICO Boulder Las Animas Bernalillo Mora Chaffee Lincoln Catron Rio Arriba Clear Creek Mesa Colfax Sandoval Conejos Mineral Curry San Juan Costilla Moffat De Baca San Miguel Crowley Montezuma Grant Santa Fe Custer Montrose Guadalupe sierra Dolores Morgan Harding Socorro Delta Ouray Lincoln Taos Denver Park Los Alamos Torrance Douglas Pitkin Luna Union Eagle Pueblo McKinley Valencia Elbert Rio Blanco El Paso Rio Grand STATE OF OREGON Fremont Routt Lake Garfield Saguache Gilpin San Juan STATE OF UTAH Grand San Miguel Beaver Piute Gunnison Summit Box Elder Rich Hinsdale Teller Cache Salt Lake Huerfano Washington Carbon San Juan Jackson Weld Daggett Sanpete Davis Sevier STATE OF IDAHO Duchesne summit Bannock Custer Emery Tooele Bear Lake Franklin Grand Uintah Bingham Fremont Iron Utah Blaine Jefferson Juab Wasatch Bonneville Madison Kane Wayne Butte Minidoka Millard Weber Camas Oneida Morgan Caribou Power Cassia Teton STATE OF WYOMING Clark Valley Albany Natrona Carbon Niobrara STATE OF MONTANA Converse Park Beaverhead Madison Fremont Platte Deer Lodge Meagher Goshen Sublette Gallatin Park Hot Springs Sweetwater Jefferson Silver Bow Johnson Teton Laramie Uinta STATE OF NEBRASKA Lincoln Weston Banner Sioux Kimball

* Counties which have substantially all of their area above 4,000 ft. Ref. Federal Register, Vol. 42, No. 76, April 20, 1977, Pg. 20464

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.