Suburban 3/4 Ton 4WD V8-305 5.0L (1986)
Fluid Pump: All Technical Service Bulletins
A/T - 700 R4 Pump Whine or Moan
Number:
87-66
Section:
7A
Date:
FEB., 1987
Subject:
PUMP WHINE OR MOAN THM 700-R4
Model and Year:
1985-87 PASSENGER CARS AND TRUCKS WITH THM 700-R4 TRANSMISSIONS
FIGURE 1 - THM 700 - R4 - TRANSMISSION I.D. NAMEPLATE
TO:
ALL CHEVROLET DEALERS
A whine or moan on a 1985 through 1987 THM 700-R4 transmission may be caused by line pressure instability in a seven-vane pump. A ten-vane pump,
to provide stable line pressure, is now used on all 1987 THM 700-R4 models and available to service 1985 and early 1987 model transmissions.
Ten-vane pumps for all 1987 THM 700-R4 production and service Replacement Transmission Assembly (SRTA) models have been used since October
28, 1986 (Julian date 301). Refer to Figure 1.
