TM 10-3930-671-24 Inching Troubleshooting Guide Inching and braking system for trucks with TA18 transaxle Condition Probable Cause Remedy 1 - Will not inch and/or partial clutch disengagement. (Cont’d) 6 Transmission inching valve spool sticking. 1) Spool or bore scored or burrs evident. 1) Replace control valve body if in bore.  Replace spool if spool bad or repair by smoothing with crocus cloth. 2) Contamination 2) Disassemble and wash. 3) Inching spool oversize or not concentric. 3) Replace spool. 4) Inching bore undersize or not concentric. 4) Replace valve body. 7. Inching spool does not fully travel. 1) Bleed down brake pedal and block as noted In bleeding procedure. 2)   Measure clutch pack pressure with parking brake applied. inching pedal fully depressed and engine idling. 3)   Clutch pressure should be 6-12 psi.  If greater, replace inching balance spring. 8. Clutch piston bleed hold plugged. 1) Complete transaxle removal, disassembly and cleaning required. 9. Clutch return spring stack has too high or 1) Remove and repair transaxle. too low spring force. 2- Will not inch in reverse only. 1. Lube oil leaking into reverse clutch. 1) Remove and repair transaxle. 3- Abrupt shift from neutral to reverse or forward. 1.Contamination in modulator. 1) Remove modulator spool and clean orifice in spool. 2.Modulator spool or bore burrs. 1) Replace control valve body if in bore.  Replace spool if spool bad, or repair by smoothing with crocus cloth. F-389