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TURBO HYDRA-MATIC 2 5 0 TRANSMISSION
7A2-7
a. Forward clutch leak (pressure low in Drive range,
pressure normal in Neutral and Reverse)
-
1. Check pump oil seal rings.
2. Check forward clutch seals.
b. Direct clutch leak (pressure low in Reverse, pressure
normal in other ranges)
-
1. Check direct clutch outer seal.
2. Check 1-2 accumulator piston and ring for damage
or missing.
Case Assembly
-
check ball missing from cored
passages in case face.
1-2 Shift
-
Full Throttle Only
Detent Valve
-
sticking or linkage misadjusted.
Vacuum Leak
-
vacuum line or fittings leaking.
Control Valve Assembly:
a. Valve body gaskets
-
leaking, damaged or incorrectly
installed.
b. Detent valve train stuck.
c. 1-2 valve stuck closed (in downshifted position).
Case Assembly
-
refer to case porosity repair above.
First Speed Only
-
No 1-2 Shift
Detent (downshift) cable
-
binding.
Governor Assembly:
a. Governor valve sticking.
b. Driven gear loose, damaged or worn (check for pin
in case and length of pin showing; also, check output shaft
drive gear for nicks or rough finish if driven gear shows
damage).
Control Valve Assembly:
a. Valve body gaskets
-
leaking, damaged or incorrectly
installed.
b. Governor feed channels blocked.
c. 1-2 shift valve train stuck closed (in downshifted
position).
Intermediate Band:
a. Servo piston seals
-
missing, improperly installed or
broken.
b. Band improperly adjusted
-
screw loose.
c. Servo apply rod broken.
Case:
a. Porosity between channels.
b. Governor feed channel blocked; governor bore scored
or worn, allowing cross pressure leak.
First and Second Speeds Only
-
No 2-3 Shift
Control Valve Assembly:
a. Valve body gaskets
-
leaking, damaged or incorrectly
installed.
b. 2-3 shift valve train stuck closed (in downshifted
position).
Direct Clutch:
a. Pump hub
-
direct clutch oil seal rings
-
broken or
missing.
b. Clutch piston seals
-
missing, improperly assembled
or cut.
c. Clutch plates burned (see BURNED CLUTCH
PLATES above).
No First Speed
-
Starts in Second Speed
(Locks up in L1 Range)
Intermediate Band:
a. Band adjustment too tight.
b. 1-2 shift valve stuck in upshift position.
Drive in Neutral
Manual Linkage
-
misadjusted (correct alignment in
manual lever shaft quadrant is essential).
Internal Linkage
-
manual valve disconnected or end
broken.
Oil Pump
-
line pressure leaking into forward clutch
apply passage.
Forward Clutch
-
incorrect clutch plate usage or
burned clutches (see BURNED CLUTCH PLATES above).
No Motion in Reverse or Slips in Reverse
(Install pressure gage)
Low Fluid Level
-
add fluid.
Manual Linkage
-
misadjusted (correct alignment in
manual lever shift quadrant is essential).
Low Oil Pressure
-
refer to Low Line Pressure above.
Control Valve Assembly:
a. Valve body gaskets
-
leaking, damaged or incorrectly
installed.
b. 2-3 shift valve train stuck open (in upshifted position).
Intermediate Servo
-
piston or pin stuck so
intermediate band is applied.
Low and Reverse Clutch
-
piston outer seal damaged
or missing.
Direct Clutch:
a. Outer seal damaged or missing.
b. Clutch plates burned (see BURNED CLUTCH
PLATES above).
Forward Clutch
-
clutch does not release (will cause
DRIVE in NEUTRAL).
Slips in All Ranges or Slips on Start
(Install pressure gage)
Low Fluid Level
-
add flu~d.
Low Fluid Pressure
-
ref& to Low Line Pressure above.
Forward Clutch:
a. Clutch plates burned (see BURNED CLUTCH
PLATES above).
b. Pump cover oil seal rings broken or worn.
Case
-
cross leaks or porosity.
Slipping 1-2 Shift
(Install pressure gage)
Low Fluid Level
-
add fluid.
Low Fluid Pressure
-
refer to Low Line Pressure above.
1-2 Accumulator
-
oil ring damaged, missing or case
bore damaged.
Pump-to-Case Gasket
-
mispositioned or damaged.
Intermediate Band:
a. Improper band adjustment.
b. Piston seals damaged or missing.
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