Caprice V8-305 5.0L (1986)
If a vehicle equipped with a THM 200-4R transmission built prior to April 25, 1986 (Julian date 115) has a harsh Park/Neutral to Drive engagement,
install the Service Package listed below.
Part Number
Description
8639943
Neutral Drive Shift Package (Contains
Forward Clutch Assembly Complete, Front
Internal Gear and Thrust Washer)
Transmissions built after April 25, 1986 (Julian date 115) can be serviced with separate parts, refer to the current GMSPO catalog.
Important:
When servicing the forward clutch, select the correct backing plate (627). Backing plate selection affects piston travel, shift feel and
clutch durability.
Figure 3
Figure 4
Backing Plate Selection:
(Clutch Fully Assembled) Apply an evenly distributed load in the direction indicated in Figure 3 to remove slack from
the clutch assembly. Use 20 lbs. (9 kg) of pressure against the backing plate -- excessive pressure will cause an
inaccurate measurement. With the clutch assembly compressed, use a feeler gage to measure the distance between the
backing plate and snap ring. Correct backing plate travel is 0.7 mm - 1.5 mm (0.028"-0.059"). Refer to Figure 4 for
backing plate identification information.
NOTICE:
Earlier design front internal gears (Service Package Number 8630909) CANNOT be used with THM 200-4R models built after April 25,
1986 (Julian date 115).
