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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

P - CLUTCH(ES) SLIPPING - HT 700 Condition Probable Causes Suggested Remedies Slipping in All Forward Ranges 1. Refer to Chart F, Probable Causes. 1. Refer to Chart F, Items 5 through 10. Slipping in Reverse Range 2. Fourth clutch defective. 2. Overhaul clutch and replace piston sealrings. 3. First clutch defective (HT 740/747, HT 750DR, HT 754CR and 2nd gear start); low clutch defective (HT 754CR without 2nd gear start). 3. Overhaul clutch and replace piston sealrings. 4. Incorrect or weak trimmer valve spring; trimmer valve stuck open. 4. Inspect trimmer valve and trimmer valve spring for correct calibration, rebuild valve body. Slipping in High and Reverse Ranges 5. Fourth clutch defective. 5. Overhaul clutch and replace piston sealrings. 6. Incorrect or weak trimmer spring; trimmer valve stuck open. 6. Inspect trimmer valve and trimmer valve spring for correct calibration, rebuild valve body. Slipping in Second or Third or Fourth Range (5-Speed) 10. Clutch defective for specific range. 10. Rebuild specific range clutch and replace piston sealrings (4th clutch, replace sealrings on center support). Slipping in Second or Third or Fourth Range (5-Speed) 11. Incorrect or weak trimmer valve spring; trimmer valve stuck open. 11. Inspect trimmer valve and trimmer valve spring for correct calibration; rebuild valve body. *NOTE: If unit is modified for split shaft PTO, all external circuitry must be removed before troubleshooting.