Skylark L4-138 2.3L DOHC VIN D MFI QUAD 4 (1989)
Clutch: All Technical Service Bulletins
A/T - Diagnosis Information, Lo-Reverse Clutch
Bulletin
89-7125-8
Date
May, '89
Ref. No.
89-140-7125
Corp. Ref. No.
977113
SUBJECT:
DIAGNOSIS INFORMATION ON THE THM 125C/HYDRA-MATIC 3T40 LO-REVERSE CLUTCH
MODEL AFFECTED:
1980-85 SKYLARKS 1982-89 SKYHAWKS 1982-89 CENTURYS 1985-89 SOMERSETS & SKYLARKS
BULLETIN COVERS
Diagnosis information given for possible inoperative Lo-Reverse Clutch assembly used in the THM 125C/HYDRA-MATIC 3T40 transaxle.
Causes for an inoperative Lo-Reverse assembly are as follows:
In the Direct Clutch area:
^
Direct Clutch Drum Center Seal that is rolled and/or cut.
This condition would cause a cross circuit leak that would apply (drag) the Lo-Reverse clutch each time the vehicle is driven in the third gear range.
^
Driven Sprocket Support Seals - check for improperly cut angles.
In Lo-Reverse Clutch area:
^
Rolled and/or cut Lo-Reverse clutch piston seals.
^
Cup Plug Seal (improperly installed) or cut.
^
Cut "O" Ring Seal on Lo-Reverse Pipe.
^
Bent and/or Leaky Lo-Reverse Pipe.
^
Bent and/or Missing Lo-Reverse Pipe Bracket.
Part Non Conformity:
^
Porosity in the # 4 and # 5 Check ball area of the case cover (cross channel leak during 3rd gear apply).
^
# 6 Check ball not seated during apply.
^
Stuck Boost Valve.
^
Backing plate out of location.
Whenever a suspect Lo-Reverse condition exists all of the previous items should be inspected and/or replaced if necessary.
SERVICE MANUAL REFERENCE
Whenever service to the Lo-Reverse Clutch Assembly is necessary refer to the THM 125C/HYDRA-MATIC 3T40 Unit Repair Section of your Service
Manual.
SERVICE NOTES
The Direct Clutch in the THM 125C/HYDRA-MATIC 3T40 is only applied in 3rd gear and Reverse - the Reverse Clutch is on in the Manual Lo and
Reverse gear ranges. If a Lo-Reverse condition exists the Direct Clutch assembly should be inspected and all components discussed under Bulletin
Covers.
