A/T - Harsh 1-2 and/or 3-4 Shifts

Number: 84-216

Section: 7A (VIIc)

Date: Nov., 1984
Subject: HARSH 1-2 AND/OR 3-4 SHIFTS


Model and Year: ALL 1984 MODEL THM 200-4R - "B" CAR WITH DIESEL ENGINE
TO: ALL CHEVROLET DEALERS


Some 1984 THM 200-4R transmissions may exhibit a harsh 1-2 and/or 3-4 shift. This harsh 1-2 and/or 3-4 shift may be caused by a damaged or mispositioned T.V. boost valve spring.

Starting April, 1984, a new control valve assembly which has a new T.V. boost valve spring went into production on all 1984 model THM 200-4R transmissions to correct this harsh 1-2 and/or 3-4 shift. (Refer to Chart 1 for part numbers and model applications and Chart 2 for Julian date breakpoints when the new control valve assembly went into production..)

On transmissions built before the Julian dates in Chart 2, if a condition of harsh 1-2 and/or 3-4 shift is experienced and the cause is the damaged or mispositioned T.V. boost valve spring, use the new control valve assembly.

FIGURE 1 - TRANSMISSION NAMEPLATE:

The Julian date is shown on the nameplate (Figure 1). The nameplate is attached to the right rear side of the transmission case.
CHART 1
NEW CONTROL VALVE ASSEMBLY MODEL AND PART NUMBER APPLICATIONS

MODELS CONTROL VALVE ASSEMBLY
PART NUMBERS

AA, AP 8639343
BQ 8639914
BT, BY 8639912
CH 8639393
CQ 8639400
CR 8639414
HE 8639424
HG 8639431
OF, OY 8639326
OG 8639452
OJ 8639462
OM 8639915
OZ 8639343


CHART 2
JULIAN DATE BREAKPOINTS WHEN NEW CONTROL VALVE ASSEMBLY WENT INTO PRODUCTION

MODEL JULIAN DATE

AA 116
BQ 109
BT 115
BY 121
CR 130
HE 125
HG 115
OG 110
OJ 114
OM 129


NOTICE: Models not listed will have the new control valve spring assembly when they are produced.