Causes Of Burned Clutch Plates; Causes Of Low Line Pressure - Jeep 1979 CJ-5 Technical & Service Manual

2C-22
AUTOMATIC TRANSMISSION
Vent Pipe Leak
@ Transmission overfilled.
• Water in fluid.
• Filter O-ring damaged or improperly assembled
causing oil to foam.
• Foreign material between pump and case or between
pump cover and body holding pump halves apart.
• Case porous or pump face improperly machined.
• Pump-to-case gasket mispositioned.
• Pump breather hole blocked or missing.
• Hole in intake pipe.
• Check ball in forward clutch housing stuck open or
missing.
Oil Cooler Lines
• Connections at radiator loose or stripped.
• Connections at case loose or stripped.
Modulator
• Diaphragm defective.
Causes of Burned Clutch Plates
Forward Clutch
• Check ball in clutch housing damaged, stuck or
missing.
• Clutch piston cracked or seals damaged or missing.
• Low line pressure.
• Manual valve mispositioned.
• Restricted oil feed to forward clutch (clutch housing
to inner and outer areas not drilled or restricted or
porous pump).
• P u m p cover oil seal rings missing, broken, or un-
dersize; ring groove oversized.
• Case valve body face not flat or porosity between
channels.
• Manual valve bent and or center land not ground
properly.
Intermediate Clutch
• Constant bleed orifice in center support missing.
• Rear accumulator piston oil ring damaged or
missing.
• One-two accumulator valve stuck in control valve
assembly.
• Intermediate clutch piston seals damaged or
missing.
• Center support bolt loose.
• Low line pressure.
® Intermediate clutch cup plug in case missing.
• Case valve body face not flat or porosity between
channels.
• Manual valve bent and center land not ground
properly.
Direct Clutch
• Restricted orifice in vacuum line to modulator (poor
vacuum response).
• Check ball in direct clutch piston damaged, stuck or
missing.
• Defective modulator bellows.
• Center support bolt loose. Bolt may be tight in, sup-
port but not holding support tight to case.
• Center support oil rings or grooves damaged or
missing.
• Clutch piston seals damaged, missing, or improperly
installed.
• Front and rear servo pistons and seals damaged.
• Manual valve bent and center land not cleaned.
• Case valve body face not flat or porosity between
channels.
• Intermediate roller clutch installed backward.
• Three-two valve, valve spring, or valve spacer pin
installed in wrong sequence in valve bore.
• Incorrect combination of front servo and accumula-
tor parts. If direct clutch plates and front band are
burned, also check manual linkage. Burned clutch
plates can be caused by incorrect usage of clutch
plates. Also, antifreeze in transmission fluid can
cause severe damage (e.g., large pieces of composi-
tion clutch plate material peeling off).
Causes of Low Line Pressure
• Low fluid level
• Oil filter plugged or restricted.
• O-ring on oil filter intake pipe omitted or damaged.
• Split or leaking intake pipe.
• Incorrect oil filter.
Oil Pump
• Pressure regulator or boost valve stuck.
• Excessive gear clearance, damaged or worn gears,
pump drive gear installed backward, or converter
pilot does not e n t e r c r a n k s h a f t freely and
completely.
• Pressure regulator spring too weak.
• Not enough spacers in pressure regulator.
• Pump-to-case gasket mispositioned.
• Defective pump body and cover.
• Mismatched pump cover/pump body.
Internal Circuit Leaks
• Forward clutch leak (pressure normal in neutral and
reverse—pressure low in drive). Check pump rings
or forward clutch seals.
• Direct clutch leak (pressure normal in neutral, low,
intermediate, and drive—pressure low in reverse).
Check center support oil seal rings.
• Check direct clutch outer seal for damage. Check
rear servo and front accumulator pistons and rings
for damage or missing parts.