Engine - Chuggle/Poor Fuel Economy/Shudder

Bulletin No. 84-70
File In Group 7
Number 101
Date Apr. '84

SUBJECT: [1][2]TORQUE CONVERTER CLUTCH, NO RELEASE OR APPLY

MODELS AFFECTED: 1982-1984 CIMARRON

FIGURE 1 - AUXILIARY VALVE BODY - COVER SIDE:

FIGURE 2 - AUXILIARY VALVE BODY GASKET:

1982-1984 Cimarrons equipped with a THM 125C transaxle may experience poor fuel economy and/or engine chuggle or shudder due to the Torque Converter Clutch (TCC) either failing to release or apply. This may be caused by a missing or mispositioned orifice cup plug in the auxiliary valve body assembly, or an eroded gasket on the auxiliary valve body cover. Beginning with September, 1983 production (transaxle numbers 84 CA 1130 and 84 CB 18587), the auxiliary valve body and gasket were changed to eliminate this condition. The new auxiliary valve body does not have a hole for an orifice cup plug (refer to Figure 1) and uses a new cover gasket with larger holes in three areas (refer to Figure 2). When servicing a THM 125C for this condition, refer to the following service and parts information.

Service Procedure

1. Perform TCC diagnosis as outlined in Section 7A of the Service Information Manual. If diagnosis indicates an auxiliary valve body condition, remove the auxiliary valve body from the transaxle following the procedures outlined in the Service Information Manual.

2. Inspect the auxiliary valve body to determine if it is the original. If the auxiliary valve body has the hole used for an orifice cup plug (refer to Figure 1), whether or not the orifice cup plug is present, proceed to Step 3. If no hole is used, proceed to Step 4.
3. ORIGINAL AUXILIARY VALVE BODY

Condition Correction

a. Orifice cup plug and auxiliary Replace gasket with P/N 8653947 and cover with valve body okay. Gasket P/N 8643645
eroded at hole #1.

b. Auxiliary valve body and Replace orifice plug with P/N 8623796 and gasket okay. Orifice cup gasket with P/N 8643239. To replace the orifice
plug mispositioned or missing. plug, remove using a 7/32 screw extractor.
Apply loctite to the new plug. Start the new plug using a 5/16 punch and seat flush with the wall using a 3/8 punch.

c. Orifice plug and gasket okay. Replace auxiliary valve body with service kit P/N 8653946 containing new auxiliary valve body, cover, and gasket. The original is no longer serviced. The auxiliary valve body included in this service kit does not contain TCC control and regulating valves, or regulator spring. If needed, these parts are available separately under the following part numbers:

Valve, TCC Control P/N 8637089
Valve, TCC Regulator P/N 8637090
Spring, TCC Regulator P/N 8637888
4. NEW AUXILIARY VALVE BODY

Condition Correction

a. Gasket eroded at hole # 1. Replace gasket P/N 8643863 and cover
Auxiliary valve body okay. P/N 8643645.

b. Gasket okay. Replace auxiliary valve body with service kit P/N 8653946 containing auxiliary valve body, cover, and gasket. The auxiliary valve body included in this service kit does not contain TCC control and regulating valves, or regulator spring. If needed, these parts are available separately under the following part numbers:

Valve, TCC Control P/N 8637089
Valve, TCC Regulator P/N 8637090
Spring, TCC Regulator P/N 8637888

When performing the listed repairs, be sure the correct gasket is used. An GMWDD stock of both original and new type gaskets are now made using a new material. The new cover is used to service both designs.

Warranty Information

Replace Auxiliary Valve Body Cover and Gasket Labor Operation No. K6545 at .9 hour.
Repair Auxiliary Valve Body
Replace Auxiliary Valve Body Labor Operation No. K6575 at 1.2 hours.
Add .1 hour to K6575 if repaired.