A/T - Burned Clutches/Cracked Turbine Shaft
Number: 84-177Section: 7A (VIIc)
Date: July, 1984
Subject: BURNED OVERRUN CLUTCH, FORWARD
CLUTCH, AND 3-4 CLUTCH PLATE ASSEMBLIES
Model and Year: ALL THM 700-R4 - 1982 THRU
1984
TO: ALL CHEVROLET DEALERS
Beginning April 16, 1984 (Julian Date 107), a new input housing and shaft assembly and oil pump assembly went into production for all models of the THM 700-R4 transmission. In addition, new torque converters went into production for all 298 mm applications (4.1L in-line L6; V8 gas and diesel engines).
FIGURE 1 - Transmission Identification:
All transmissions built starting with Julian Date 107 are stamped with the letter "T" on the pan rail after the transmission identification number (Figure 1). The letter "T" will only be used for the remainder of the 1984 model year.
These production changes eliminate the possibility of burned clutch packs in the input housing due to hairline cracks which could develop across the ring grooves in the turbine shaft. A crack in this area of the turbine shaft on models built prior to this change could cause one or any combination of the following clutches to slip and overheat due to loss of apply pressure:
A. Overrun Clutch Pack
B. Forward Clutch Pack
C. 3-4 Clutch Pack
SERVICE INFORMATION
1. If any 1982, 1983 or 1984 THM 700-R4 transmission (built prior to Julian Date 107) experiences burned clutch packs within the input housing assembly, check for a possible cracked turbine shaft.
FIGURE 2 - Stator Shaft Sleeve:
IMPORTANT: A hairline crack in the turbine shaft is not always detected by visually inspecting the shaft. To determine if the shaft is cracked, inspect the stator shaft sleeve for possible score marks in the inner diameter (Figure 2). If scoring is found, the probable cause is a crack in the turbine shaft which opens under torque conditions and produces the scoring and burned clutch packs. If this condition is found, replace both the input housing and shaft assembly and the oil pump assembly complete. Due to recent changes in the oil pump cover and pump body castings, these parts are serviced as an assembly for 1982 through 1984..
2. Oil pump assemblies, input housing and shaft assemblies, and converters can be purchased separately as shown in the following Charts #1, #2, and #3, respectively. However, any transmission built prior to this change (1982, 1983, or 1984 not identified by a "T") must use the part numbers shown in the column marked "before Julian Date 107". Any 1984 transmission built after this change (identified by the letter "T") must use the part numbers in the column marked "after Julian Date 107".
3. Due to the numerous changes made on the above parts, those shown for use prior to the change must not be interchanged with those shown for use after the change. Interchanging these parts will result in conditions such as:
A. Interference fits
B. Loose fits
C. No drive
D. Possible repeat cracks in the turbine shaft
E. Future confusion if the transmission should require additional service.
CHART 1
YEAR MODELS PART NAME BEFORE STARTING
JULIAN DATE WITH JULIAN
107 DATE 107
1982 T5, YK, YL, T6, TW, YA,
TC, TE, TH, TJ, TK, M2, OIL PUMP
M4, M5, M7, MB, MC, MD, ASSY. COMPLETE 8647967
ME, Y3, Y4, Y6
1982 M6, MH, TN, TP OIL PUMP 8647968
ASSY. COMPLETE
1983 TC, MB, MC, MJ, VN, TE,
TH, TK, MD, ME, MW, VH, OIL PUMP
T2, VA, YN, ML, MP, MS, ASSY. COMPLETE 8647967
T7, MK, YG, PQ, YP, YK, Y9, YF
1983 YH, TS, TZ, T8, TP, MH, OIL PUMP 8647968
VJ, TL ASSY. COMPLETE
1984 MB, MC, MD, VH, TE, ME,
MK, MJ, VN, TC, TH, MW, OIL PUMP
TK, VA, YF, PQ, YG, YP, ASSY COMPLETE 8647967
YK, Y6, YN, YA, Y9, YW
1984 TL, TZ, ML, MP, MS, T7, Oil Pump
YH, Y7, Y8, TS, MR, TG, ASSY. Complete 8647968 8654309
TD
1984 MH, VX, VJ, VE, TM, T8, OIL PUMP
MG ASSY. COMPLETE 8647969 8654310
CHART 2
YEAR MODELS PART NAME BEFORE STARTING
JULIAN DATE WITH JULIAN
107 DATE 107
1982 T5, YK, YL, T6, TW, YA,
TC, TE, TH, TJ, TK, M2, INPUT HOUSING *8647127
M4, M5, M7, MB, MC, MD, AND SHAFT ASSY. (8647963)
ME, Y3, Y4, Y6, M6, MH, TN, TP
1983 TC, MB, MC, MJ, VN, TE,
TH, TK, MD, ME, MW, VH, INPUT HOUSING *8647127
TZ, MK, YN, YF, YG, YP, AND SHAFT ASSY. (8647963)
YK, Y9, TS, T8, TP, MH, VJ, TL
1983 T2, VA, ML, MP, MS, T7, INPUT HOUSING *8647128
YH, YF, PQ AND SHAFT ASSY. (8647965)
1984 MB, MC, MD, VH, MR, TG,
ME, MK, MJ, VN, TC, TH,
MW, TD, TK, MG, MH, VX, INPUT HOUSING *8647127
VJ, TL, VE, TM, TZ, T8, AND SHAFT ASSY. (8647963) 8654156
TE, YP, Y8, TS, YK, Y6, YN, YA, Y9, YW, YG
1984 VA, ML, MP, MS, T7, YH, INPUT HOUSING *8647128
YF, PQ, Y7 AND SHAFT ASSY. (8647965) 8654155
* These part numbers will be superseded by the numbers shown in ( ) Approx. in October 1984.
Torque converter assemblies for 1982, 1983, and 1984 models built prior to Julian Date 107, use current released part numbers.
Torque converter assemblies for 1984 models starting with Julian Date 107, use the part numbers as shown in the chart below:
CHART 3
1984 MODEL TORQUE CONVERTER ASSEMBLY PART NUMBERS STARTING WITH JULIAN DATE 107
MG, MH, VX, VJ, VE, TM, CONVERTER ASSY. 8647903
TZ, T8
YK, Y6, MD, VH, MR, TG,
TE, ME, MK, TH, MK, TH, CONVERTER ASSY. 8647901
MW, TD, TK
Y8 CONVERTER ASSY. 8647900
YG, TS, YN, YA, Y9, YW, CONVERTER ASSY. 8647904
YP, MB, MC, MJ, VN, TC CONVERTER ASSY. 8647902