Mercury MerCruiser D2.8L D-Tronic Service Manual page 145

SERVICE MANUAL NUMBER 22
ZF / Hurth Hydraulic Transmission (continued)
15. Transmission
16. Chattering
90-860074--1 FEBRUARY 2002
Trouble
15. A. Fluid level too low so
noise changes,
becomes louder
16. A. The engine or
transmission noise
mainly at low
speed
Possible Cause
that pump sucks in air
B. Damage starting on
flexible coupling due to
wear or fatigue, possible
due to misalignment
between engine and
transmission
C. Beginning damage of
bearings in transmission;
torsional vibrations,
running without fluid,
overload, wrong alignment
of transmission, excessive
engine output
D. Beginning damage of
gearings; torsional
vibrations, running
without, fluid, overload
E. Fluid baffle on
transmission has come
loose
F. Fluid suction pipe in
transmission has come
loose
propeller generate
torsional vibrations, which
produce a chattering noise
in the transmission
B. Misaligned cardan
shafts on input or output
shafts
TROUBLESHOOTING
Remedy
15. A. Top off fluid to fill mark
B. Replace flexible
coupling. Check alignment
between engine and
transmission
C. Disassemble
transmission, replace
bearings concerned and
other faulty parts
D. Disassemble
transmission, remove
faulty parts
E. Disassemble
transmission,attach baffle
plate
F. Disassemble
transmission, fix fluid
suction pipe
16. A. Mount a flexible
coupling with another
stiffness factor between
engine and transmission;
a coupling with a higher
stiffness factor might be
sufficient
B. Mount and align
cardan shaft strictly
according to instructions
issued by cardan shaft
manufacturer
Page 1C-39