For 1990-2009 cars

# NO UPSHIFT AFTER A PART OR FULL THROTTLE DETENT

#### MODELS AFFECTED: 1984-1985 THM 325-4L TRANSMISSIONS

#### NOTE: This bulletin supersedes bulletin 85-735-5A, dated July, 1986. Part No. 8639935 was incorrectly listed as Part No. 8639335. Please discard 85-735-5A.

A 1984 through 1985 THM 325-4L transmission may exhibit a no upshift condition after a part or full throttle downshift.

This condition may be caused by internal leakage hydraulically locking the throttle valve plunger. If this occurs, the line pressure remains at a boosted level, resulting in a no upshift condition.

To repair this condition, a new throttle valve plunger and throttle valve bushing, and for some models, a throttle valve lever and bracket assembly should be installed. Refer to Figure 1 for transmission nameplate identification information and to Figure 2 for service parts identification. The chart provided indicates service package part numbers and transmission model applications.

#### IMPORTANT: The highlighted transmission models and service package part numbers identify those packages which include the throttle lever and bracket assembly. These service packages were not included in the original bulletin. **1986 * SERVICE PACKAGE TRANSMISSION MODEL TRANSMISSION PART NUMBER JULIAN MODEL AND YEAR DATE 1985 1984

8639935 THM 325-4L N/A AL, OK AL, OK 8639936 THM 325-4L N/A OE, OQ OE, OQ 8369937 THM 325-4L N/A BE

* The Highlighted service packages contain:

(1) Throttle valve plunger (1) Throttle valve plunger bushing, and (1) Throttle lever and bracket assembly.

All other service packages contain:

(1) Throttle valve plunger and (1) Throttle valve plunger bushing.

(NOTE: Throttle lever and bracket assembly part number 8648670 is available separately)

** 1986 Model Julian date begins in calendar year 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.