Dodge RAM TRUCK 1500 1995 Service Manual page 253

6 - 4 CLUTCH
B R
Careful observation during a road test will help
narrow the problem area.
CLUTCH PROBLEM CAUSES
CONTAMINATION
Fluid contamination is one of the more common
causes of clutch malfunctions. Oil, water, or clutch
fluid on the clutch contact surfaces will result in
faulty operation. The usual result is chatter, slip, or
grab.
During inspection, note if any components are con­
taminated with oil, hydraulic fluid, or water/road
splash.
Oil contamination indicates a leak at either the
rear main seal or transmission input shaft.
Oil leakage produces a residue of oil on the housing
interior and on the clutch cover and flywheel.
Heat buildup caused by slippage between the cover,
disc and flywheel, can sometimes bake the oil residue
onto the components. The glaze-like residue ranges
in color from amber to black.
Road splash contamination means dirt and water
are entering the clutch housing due to loose bolts,
housing cracks, vent openings, or through the slave
cylinder opening. Driving through deep water pud­
dles can force water/road splash into the housing
through such openings.
An additional problem caused by water contamina­
tion and especially by steam cleaning, involves clutch
disc sticking and poor release.
Water and steam vapors can be absorbed by the
clutch facing material. If the vehicle sits idle for long
periods after water contamination, the force exerted
by the pressure plate may cause the disc to bond it­
self to the flywheel or pressure plate.
Frequently, the only remedy for the above condition
is component replacement. To avoid this problem, a
vehicle should be driven as soon as possible to heat
and dry the clutch components.
Clutch fluid leaks are from a loose or damaged
slave cylinder line or connection. However, clutch
fluid leaks will usually be noted and corrected before
severe contamination occurs.
CLUTCH MISALIGNMENT
Clutch components must be in proper alignment
with the crankshaft and transmission input shaft.
Misalignment caused by excessive runout or warpage
of any clutch component will cause grab, chatter and
improper clutch release.
Flywheel Runout
Common causes of runout are heat warping, im­
proper machining, mounting the flywheel on a dirty
crankshaft flange, incorrect bolt tightening, or im­
proper seating on the crankshaft flange shoulder.
Very light scratches or surface roughness on the
flywheel face can be cleaned up by scuff sanding with
180 grit emery cloth. However, if the surface is
warped or severely scored, replace the flywheel.
Clean the crankshaft flange before mounting the
flywheel. Dirt and grease on the flange surface may
cock the flywheel causing runout.
Use new bolts when remounting a flywheel and se­
cure the bolts with Mopar Lock And Seal, or Loctite
242. Tighten flywheel bolts to specified torque only.
Overtightening could distort the flywheel hub caus­
ing runout.
Clutch Cover And Disc Runout
Check the clutch disc before installation. Axial
(face) runout of a new disc should not exceed 0.5 mm
(0.020 in.). Measure runout about 6 mm (1/4 in.) from
the outer edge of the disc facing. Obtain another disc
if runout is excessive.
Check condition of the clutch before installation. A
warped cover or diaphragm spring will cause grab
and incomplete release or engagement.
Be careful when handling the cover and disc. Im­
pact can distort the cover, diaphragm spring, release
fingers and the hub of the clutch disc.
Use an alignment tool when positioning the disc on
the flywheel. The tool prevents accidental misalign­
ment which could result in cover distortion and disc
damage.
A frequent cause of clutch cover distortion (and
consequent misalignment) is improper bolt tighten­
ing. To avoid warping the cover, tighten the bolts al­
ternately (in a diagonal pattern) and evenly (2-3
threads at a time) to specified torque.
Clutch Housing Misalignment And Runout
Clutch housing alignment is important to proper
operation. The housing bore maintains alignment be­
tween the crankshaft and transmission input shaft.
Misalignment can cause noise, incomplete clutch
release and chatter. It can also result in premature
wear of the pilot bearing, cover release fingers and
clutch disc. In severe cases, misalignment can. also
cause premature wear of the transmission input
shaft and bearing.
Housing face misalignment is generally caused by
incorrect seating on the engine or transmission, loose
housing bolts, missing alignment dowels or housing
damage. Infrequently, misalignment may also be
caused by housing mounting surfaces that are not
parallel.
If housing misalignment is suspected, the housing
is probably not fully seated on either the engine,
alignment dowels, or transmission front face. Since
the NV3500 clutch housing is an integral part of the
transmission front case, it will be necessary to re­
move the transmission and housing as an assembly
to check seating. Housing bore and face runout can