A/T - THM 700-R4 Harsh Shifting

88chevy27

Number: 88-323-7A

Section: 7A

Date: AUGUST, 1988
Subject:
1-2 WIDE OPEN THROTTLE "END BUMP" AND/OR 3-2 HIGH SPEED "TIE-UP"


Model and Year: 1988 CAPRICE WITH 4.3L ENGINE AND THM 700-R4 TRANSMISSION
TO: ALL CHEVROLET DEALERS


This bulletin covers service parts for a 1988 YTM model THM 700-R4 transmission, which may exhibit a 1-2 wide open throttle "end bump" and/or 3-2 high speed "tie-up". An end bump" is a firmer feel at the end of the shift as compared to the feel at the start of the shift. A "tie-up" is a condition where two opposing clutches, or band and clutch, are attempting to apply at the same time. A new 1-2 Accumulator Spring and new Valve Body Spacer Plate were introduced to improve shift feel and timing.

FIGURE 1 - THM 700-R4 TRANSMISSION IDENTIFICATION INFORMATION:

DATE OF PRODUCTION CHANGE: (Figure 1)

Beginning March 28, 1988 (Julian Date 088) all 1988 YTM model THM 700-R4 transmissions were produced with the new 1-2 accumulator spring and valve body spacer plate.

FIGURE 2:

SERVICE ACTION: (Figure 2)

The Service Package listed in "Service Parts Information" can be used on any 1988 YTM model THM 700-R4 transmission (built prior to Julian Date 088) that exhibits a 1-2 wide open throttle end bump and/or 3-2 high speed tie-up.
SERVICE PARTS INFORMATION:

Service Pkg. No. Contents

8649997 Instruction Sheet
Spring, 1-2 Accumulator (59) Plate, Valve Body Spacer (56) Gasket, Spacer Plate To Case (88) Gasket, Spacer Plate To Valve Body (89) Gasket, Transmission Oil Pan (72)

Parts are currently available from GMSPO.