A/T Troubleshooting for Lo-Reverse Clutch in 6000 V6-260 Diesel Model
Clutch: All Technical Service Bulletins
A/T - Diagnosis Information, Lo-Reverse Clutch
Bulletin Number:
89-7-27
Reference Number:
977113
Publish Date:
5/89
DIAGNOSIS INFORMATION ON THE THM
Subject:
125C/HYDRA-MATIC 3T40 LO-REVERSE CLUTCH
Models
Affected:
1980 - 1989 6000, SUNBIRD, GRAND AM AND LEMANS MODELS
Diagnosis information is 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/HYDR-A-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.
