TROUBLESHOOTING /SYSTEM PERFORMANCE

A-5. Poor traction

（１）Internal leakge and sticky movement of HST motor system press ure control section

If no abnormalities are found in all the preceding checks and st ill the traction of the machine is poor, the incli-nation of the motor's swash plate is not switched to t he large capacity position (large-torque, low-speed position) from the small capacity position (small-torque, high-speed position).

Faulty HST motor

Troubleshooting

A-6.Machine travels when engine is running at low idle speed

（１）Engine low idle speed is too high.

Measure the low idle speed of the engine

Measure the engine low-idling speed in accordance with the descr iption in the section of measurements of engine performance, “Engine speed.”

Refer Performance standard list for standard value.

1. Adjustment of the accelerator linkage is faulty, so its lever does not come in contact with the minimum speed stopper even when the accelerator pedal is released.

2. Foreign matter jammed in the accelerator pedal prevents it from returning fully.

3. The accelerator linkage is rusted and/or sticking.

Poor air bleeding of HST system or damage to AU control section

Troubleshooting

TROUBLESHOOTING /SYSTEM PERFORMANCE

A-6.Machine travels when engine is running at low idle speed

（２）Poor air bleeding of HST system or damage to AU control secti on

1. If the machine travels with the shift lever in the "neutral" position, check the hydraulic fluid (pay attention to viscosity).

2. If the machine travels only momentarily just after engine sta rt with the shift lever in the "neutral" position, bleed air out of the HST system. Air may remain in the system when the hydraulic fluid filter or its element is replaced, the HST pump or motor is r epaired, or the HST piping and hoses are replaced. If such replacement or repair is not a cause, air m ay have entered the system from loose connection of the HST piping and hoses; check the connnectors and tighten the fittings as necessary.

3. If, even after air bleeding, the machine travels with the shi ft lever in the "neutral" position, damage to the AU control section and/or faulty neutral control secti on are assumed to be the cause. Proceed to "Faulty HST pump".

Troubleshooting

A-7.HST fluid level lowers rapidly

（１）Faulty HST motor rear oil seal, or internal leakage of parkin g brake

If the hydraulic fluid level lowers and the reduction oil is dis charged together with air from the breather, the hydraulic fluid may have leaked into the reduc tion gear due to faulty HST motor oil seal, or hydraulic fluid is internally leaking after f lowing through the parking brake control system due to damaged parking brake piston in the reduct ion gear.

Caution: Repair the faulty sections immediately as operating the machine with insufficient oil will cause serious accidents possibly resulting from seizure or sticking-up of the MST pump and motor.

Troubleshooting

TROUBLESHOOTING /SYSTEM PERFORMANCE

Ａ-8.Oil leakage from axle or reduction gearbox

（１）Oil leakage from around nut ② of front axle drive pinion ①

Excessive play in spline coupling between drive pinion ① and input flange ③

Faulty O-ring ④ of splined section

Remove the nut ② and turn the input flange ③ by hand to check th e spline coupling for excessive

Excessive play. No excessive play.

Replace the drive pinion ① or input flange ③.

Replace the O-ring ④

Troubleshooting

TROUBLESHOOTING /SYSTEM PERFORMANCE

Ａ-8.Oil leakage from axle or reduction gearbox

（２）Oil leakage from oil seal at input flange ③ of front axle

Faulty oil seal ⑤ or worn seal rubbing surface of input flange ③ Worn or damaged bearings ⑥ and ⑦

Turn the input flange ③ by hand, and check the flange for excess ive play.

Excessive play No excessive play

Replace the bearings ⑥ and ⑦.

Replace the oil seal ⑤ or input flange ③.

Troubleshooting

TROUBLESHOOTING /SYSTEM PERFORMANCE

Ａ-8.Oil leakage from axle or reduction gearbox

（３）Oil leakage from around nut ② of front axle drive pinion ①

Faulty oil seal ①

Worn or damaged bearings ③ and ④

Remove the wheel and move the drive shaft ② flange by hand to ch eck for excessive play in axial and circumferential directions.

Excessive play No excessive play

Replace the bearings ③ and ④.

Replace the oil seal ①

Troubleshooting

TROUBLESHOOTING /SYSTEM PERFORMANCE

Ａ-8.Oil leakage from axle or reduction gearbox

（４）Oil leakage from around nut ② at reduction gearbox output fla nge ①

Excessive play in spline coupling between shaft ③ and output flange ①

Faulty O-ring ④ at splined section

Remove the nut ② and turn the output flange ① by hand to check t he spline coupling for excessive play.

Excessive play No excessive play

Replace the shaft ③ or output flange ①.

Replace the O-ring ④

Troubleshooting

TROUBLESHOOTING /SYSTEM PERFORMANCE

Ａ-8.Oil leakage from axle or reduction gearbox

（５）Oil leakage from oil seal ⑥ / ⑦ of output flange ① / ⑤

Faulty oil seals ⑥ / ⑦ or worn seal rubbing surface of output flange ① / ⑤

Worn or damaged of bearing ⑧ / ⑨

Turn the output flange ① or ⑤ by hand to check the flange for excessive play.

Excessive play No excessive play

Replace the bearing ⑧ / ⑨.

Replace the oil seal ⑥ / ⑦ or output flanges ① / ⑤.

Troubleshooting