Troubleshooting - Parker 732 Series Owner's Manual

Bulletin HY25-1900-M1/US

Troubleshooting

Troubleshooting
Driver Training: One of the major causes of bearing and gear failures in the auxiliary unit is poor driving habits.
Drivers should be taught to always use the Lo Speed or reductions available in the auxiliary unit and keep the
front box in the higher ratios not vice versa.
Worn and pitted gears, as well as worn and pitted bearings are usually caused by excessive use of the auxiliary
overdrive gears with the main box in lower gear ratios.
Broken teeth in the auxiliary unit are usually caused by drivers trying to start their vehicles with the auxiliary unit
in the high ratio while the big reduction is made in the front box. Frogging or quick release of clutch gives a jump
start which is also noted for breaking teeth.
Noisy Operation: Noise is usually very elusive and generally not the fault of the auxiliary; therefore, mechanics
should road test to determine if the driver's complaint of noise is actually in the auxiliary. Remember that auxiliary
units act as sounding boxes and in numerous instances, drivers have insisted that the noise was in the auxiliary.
However, investigations revealed the noise to be caused by one of the following conditions:
A. Fan out of balance or bent blades.
B. Defective vibration dampers.
C. Crankshafts out of balance.
D. Flywheels out of balance.
E. Flywheels mounting bolts loose.
F. Engine rough at idle producing rattle in gear train.
G. Clutch assembly out of balance.
H. Engine mounts loose or broken.
I. PTO gear not fully engaged or housing not properly shimmed.
J. Universal joints worn out.
K. Propeller shafts out of balance.
L. Universal joint angles out of plane or at an excessive angle.
M. Center bearings in driveline dry, not mounted properly, etc.
N. Wheels out of balance.
O. Tire treads humming or vibrating at certain speeds.
P. Air leaks on suction side of induction system—especially with turbo-chargers.
Mechanics should try to locate and eliminate noise by means other than auxiliary removal, or overhaul. However, if
the noise appears to be in the auxiliary, try to break it down into the following classifications. If possible, determine
what position the gear shift lever is in when the noise occurs. If the noise is evident in only one gear position, the
cause of the noise is generally traceable to the gears in operation.
A. Growling and humming or, more serious, a grinding noise. These noises are caused by worn, chipped,
rough, or cracked gears. As gears continue to wear, the grinding noise will be noticeable, particularly in the
gear position that throws the greatest load on the worn gear.
B. Hissing or, more serious, a thumping or bumping type noise. Hissing noises can be caused by bad
bearings. As bearings wear and retainers start to break up, etc., the noise could change to a thumping or
bumping.
C. Metallic rattles within the auxiliary usually result from a variety of conditions. Engine torsional vibrations are
transmitted to the transmission through the clutch, which may be amplified and transmitted to the auxiliary
through the connecting propeller shaft. In heavy duty equipment, clutch discs with vibration dampers are
not used, so a rattle, particularly in neutral, is common with diesel equipment. In general, engine speeds
should be 600 RPM or above to eliminate objectionable rattles and vibration during the idle. Always leave
the main box in neutral and the auxiliary unit in gear when idling. A defective or faulty injector would cause
a rough or lower idle speed and a rattle in the auxiliary. Rattle could also be caused by excessive backlash
in PTO unit mounting.
D. Improper lubricants or lack of lubricant can produce noises. Auxiliaries with low oil levels sometimes run
hotter than normal, as there is insufficient lubricant to cool and cover the gears.
Owner's Manual
Legacy Split Shafts and Gear Box
27 Parker Hannifin Corporation
Chelsea Products Division
Olive Branch, MS 38654 USA