Suburban 3/4 Ton 4WD V8-305 5.0L (1986)
Clutch: All Technical Service Bulletins
A/T - THM 400 New Forward and Direct Clutch Assemblies
SIL 88-16 (Apr)
Subject: THM 400
TRANSMISSION MODELS:
FDA, FFA, FJA, FMA, FNA, FPA, FQA, FTA, FUA FWA, FYA, FZA, LAA, LBA, LCA, LDA, LFA, LHA LJA, LKA, LMA, LRA, LSA, LTA, LUA,
LWA, LZA
BULLETIN COVERS:
Certain 1987 and 1988 light duty models with THM 400 transmission (refer to list above) have new forward and direct clutch assemblies with a "dished"
steel clutch plate. This new design clutch plate improves forward and reverse engagement shift feel by cushioning piston apply.
DATE OF CHANGE: (Figure No. 1)
July 22, 1936 (Julian Date 203) for listed 1987 THM 400 transmission models.
SERVICE ACTION: (Figures No. 2 and No. 3)
When servicing the forward and/or direct clutch, inspect the "dished" clutch plate (# 612, Figure No. 2 and # 624, Figure No. 3) for scoring. cracks, or
flatness.
Also, when servicing the direct clutch assembly, note position of the two 2.32 mm (.0915"), and three 1.97 mm (.7775"), flat steel plates (Figure No. 3,
Item 622). To properly assemble the direct clutch pack, follow the dished steel plate with: a .0915 steel plate, fiber plate, the second .0915" steel plate,
and complete by alternating fiber and .0775" steel plates.
SERVICE PARTS INFORMATION:
Part Number Description
8625196 .054" Dished Clutch Plate
8623849 .0775" Flat Clutch Plate
8625197 .0915" Flat Clutch Plate
SERVICE NOTE:
The new forward and direct clutch assemblies cannot be used for past model service as other 1987-88 calibration changes contribute to the improved
engagement shift feel.
