A/T - THM 125C New Clutches/Repair Packages
Number: 87-133Section: 7A
Date: MAY, 1987
Subject: NEW FORWARD CLUTCH ASSEMBLY AND
NEW LO AND REVERSE CLUTCH ASSEMBLY
Model and Year: 1985-87 MODELS WITH THM 125C
Figure 1 - THM 125/125C TRANSAXLE Identification Information:
TO: ALL CHEVROLET DEALERS
A new forward clutch assembly entered production July 3, 1986 (Julian date 184 - refer to Figure 1). This assembly includes: a new housing, new piston, new selective backing plates, and an additional wave plate for improved neutral to drive shift feel.
A new Lo/Reverse clutch housing and Lo/Reverse clutch pack assembly entered production July 8, 1986 (Julian date 189 - refer to Figure 1). The Lo/Reverse housing assembly includes: a new housing, new piston, two wave plates, and selective backing plates for improved neutral to reverse shift feel. The Lo/Reverse clutch pack assembly includes:
wave, steel, compositioned-faced, and selective backing plate, and is serviced as an assembly only.
To Service 1985 and 1986 (before Julian date 184) THM 125-C
The neutral to drive package can be used to service a 1985 or 1986 (before Julian date 184) THM 125C transaxle exhibiting a harsh drive engagement by replacing the forward clutch with the new forward clutch assembly.
The neutral to reverse package can be used to service a 1985 or 1986 (before Julian date 189) THM 125C transaxle exhibiting a harsh reverse engagement by replacing the lo and reverse clutch assembly with the new lo and reverse housing assembly, and new lo and reverse clutch pack assembly. (The lo and reverse clutch pack assembly contains both wave plates, the steel and compositionedfaced plates, and the correct selective backing plates.)
To Service 1986 (after Julian date 184) and 1987 THM 125C
When servicing the forward clutch assemblies on a 1986 (after Julian date 184) or 1987 THM 125C transaxle, it is important to select the correct backing plate. The backing plate selection effects piston travel and shift feel.
Figure 2 - Forward Clutch Backing Plate Selection:
To check the forward clutch backing plate selection, after assembling the clutch pack into the housing, press down on the backing plate with approximately 10 lbs. of force and check the gap between the backing plate and snap ring. If the gap is larger than 1.49 mm use the next thicker backing plate, and if smaller than 0.67 use the next thinner backing plate. Refer to Figure 2 for alternate backing plate selections.
To service the lo and reverse clutch housing and/or lo and reverse clutch pack assembly, order the required part or parts listed below.
SERVICE PARTS INFORMATION
Part Number Part Name
8664167 Forward Clutch Assembly, Complete
8664152 Lo and Reverse Clutch Housing Assembly
8664151 Lo and Reverse Clutch Pack Assembly