A/T - Late Engagement or Slipping In Drive

Number: 84-12

Section: VIIc

Date: Oct., 1983
Subject: LATE ENGAGEMENT OR SLIPPING IN DRIVE


Model and Year: 1984 THM 200C

FIGURE 1 - SLIPPING DRIVE RANGE:

TO: ALL CHEVROLET DEALERS


Some early 1984 model THM 200C transmissions may experience a late engagement or slipping in drive range. This condition is usually detected while the transmission is cold, and could be caused by a blocked forward clutch feed orifice hole (see Figure 1).
Other causes for late engagement or slipping in drive are, low transmission oil level cut or nicked forward clutch piston seals and/or cut or nicked teflon (R) turbine shaft seals.

This bulletin is for early 1984 model THM 200C transmissions. Refer to the chart below and verify serial model numbers. If the serial number is prior to the number on the chart then follow this procedure.
MODEL SERIAL NUMBER


BH 54628
OI 21738
CZ 1041
JY 1075
OR 1119
OU 1727


SERVICE PROCEDURE

1. Check transmission oil level correct if required.

2. Visually inspect the forward clutch piston seals and turbine shaft teflon (R) seals for cuts and nicks.

FIGURE 2 - ALLEN WRENCH:

FIGURE 3 - ALLEN WRENCH INTO CLUTCH FEED:

3. Using a 1/16" allen wrench mark short end as illustrated in Figure 2. Using the allen wrench as a gage, insert the small end into the forward clutch feed orifice hole (Figure 3) and make sure the allen wrench goes into the orifice hole (without any drag) until the mark on the wrench is flush with the ground diameter (Figure 3).

If it is necessary to replace any of the parts listed in this bulletin, refer to the chart below:


Housing Assembly Forward Clutch Turbine Shaft
Model Forward Clutch Piston Seals Seals (Teflon R)

CZ, JY 8633948 8628924
ALL MODELS 8628090

BH, OI,
OR, OU 8638944 8628924