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Allison Transmission Parts

Troubleshooting Charts For Allison Transmissions AT / MT (B) / HT / V
The troubleshooting information contained in the following charts outlines the possible causes of transmission conditions and their remedies. Several possible causes are indicated; numbered items indicate suggested remedies for the causes. For Sales and Service Call America's #1 Supplier of OEM Allison Transmission Parts and Authorized Allison Dealer;
TransDiesel Transmission Call us: 1-407-295-1221

F - CLUTCH(ES) SLIPPING*
Condition Probable Causes Suggested Remedies
Slipping and Chatter in Only One Range 1. Specific clutch defective. 1. Rebuild the specific clutch.
2. Specific clutch piston seals leaking. 2. Rebuild specific clutch and piston assembly.
3. Transmission fluid leaking past control valve components for specific gear. 3. Replace or rebuild control valve body assembly.
4. Trimmer valve stuck open. 4. Replace or rebuild trimmer valve.
5. Cycling priority valve. 5. Replace or rebuild control valve body assembly. Inspect priority valve.
Slipping in All Forward Ranges 6. Transmission fluid level low. 6. Add transmission fluid to proper level. (Be sure dipstick calibration is correct for specific model.)
7. Main pressure low. 7. Refer to Chart E, Low Pressures.
8. Forward clutch defective. 8. Rebuild forward clutch.
9. Sealrings on front support hub worn or broken. 9. Replace sealrings.
10. Lubrication valve stuck open. (Not applicable for AT s and V s.) 10. Inspect valve for contamination and proper operation.
11. Centrifugal check balls not seating (forward and/or fourth clutches.) 11. Inspect check balls for contamination and proper operation.
* NOTE: If unit is modified for split shaft PTO, all external circuitry must be removed before troubleshooting.