CLUTCH AND TRANSMISSIONS 7-14
SPEED HEAVY DUTY TRANSMISSION
(WARNER MODEL T 16)
INDEX
General Description ......
Maintenance and Adjustments
Shift Linkage Adjustment
Side Cover ........
Removal .........
Disassembly
7-14
7-14
7-14
7-14
7-14
7-14
Assembly 7-14
Installation • 7-15
Other Maintenance
&
Adjustment
Operations See 3-Speed Saginaw Section
Transmission Replacement . . . See 3-Speed Saginaw Section
GENERAL DESCRIPTION
The Borg-Warner heavy duty three speed fully syn-
chronized (all forward gears) transmission incorporates
helical gears throughout specially designed to provide
high torque capacity, and gear teeth proportion to operate
at high speeds with neither excessive heat generation nor
excessive frictional losses. Shafts, bearings, high ca-
pacity clutches and other precision parts are held to
close limits providing proper clearances necessary for
durability during extended heavy usage.
The main drive gear is supported by a heavy duty ball
bearing at the front end of the transmission case and is
piloted at its front end in an oil impregnated bushing
mounted in the engine crankshaft. The front end of the
mainshaft is piloted in a row of roller bearings set into
the hollow end of the main drive gear and the rear end
is carried by a heavy duty ball bearing mounted in the
front of the extension housing.
The countergear is carried on a double row of rollers
at both ends while thrust is taken on thrust washers lo-
cated between the ends of the gear and the thrust bosses
in the case. An anti-rattle plate assembly at the front
of the countergear provides a constant spring tension be-
tween the counter and clutch gears to reduce torsional
vibrations. The reverse idler gear is carried on 25
roller bearings while thrust is taken on thrust washers
located between the ends of the gear and the thrust bosses
of the case.
Gear shifting is manual through shift control rods from
the shifter tube in the mast jacket to the rearward shift
lever of the side cover assembly for first and reverse
gear; and through a cross shaft assembly attached to the
forward side cover lever for second and third gear. All
three forward gears are fully synchronized. The syn-
chronizer assemblies consist of a clutch hub, clutch
sleeve, two clutch key springs and three energizer clutch
keys and are retained as an assembly on the main shaft
by a snap ring. The transmission may be used as an aid
in deceleration by downshifting in sequence without
double-clutching or any gear clashing. Reverse is not
synchronized, however, it is a helical gear to insure
quiet operation.
MAINTENANCE AND ADJUSTMENTS
Refer to similar procedures under the 3-speed Saginaw
Transmission Section for—Column Mounted Shift Linkage
Adjustment, Speedometer Driven Gear and Oil Seal Re-
placement, Extension Oil Seal Replacement and Trans-
mission Replacement. ~~
Camaro and Corvette Floor Shift Linkage Adjustment
(Fig.
lc)
1.
Set Lever (L), (K) in neutral position.
2.
Move Lever Assembly (A) and Levers (C), (D) to
neutral position and insert Locating Gauge (B) into
control Lever Bracket Assembly.
3.,
Install Rod (H) with Retainer (M) on Lever (L).
4.
With two Jam Nuts (G), (E) and Swivel (F) loose on
Rod (H) insert and attach Swivel with Retainer (N)
to Lever (D).
5.
Repeat steps 3 and 4 for Rod (J) and Levers (C
&
K).
6. Remove' Locating Gauge and check shift to insure
proper operation.
SIDE COVER ASSEMBLY
Removal
1.
Drain transmission and disconnect control rod and
cross shaft from side cover levers. *
2.
Remove nine cap screws securing the transmission
side cover assembly to transmission, case and re-
move cover assembly, shifting forks, and gasket.
Disassembly (Fig. 2C) '
1.
Remove shifting forks from shift lever assemblies.
2.
Remove nut and lock washer from each shift lever
shaft.
3.
Remove outer shift levers and lightly tap shift lever
shafts from assembly.
4.
Remove two steel balls, poppet spring, interlock pin
and interlock sleeve from cover.
5.
Remove "O" ring seals from shift lever shafts.
Assembly (Fig. 2C)
1.
Install new "O" ring seals to shift lever shafts.
2.
Install low and reverse shifter shaft and plate as-
sembly to cover.
3.
Place shifter shaft and plate assembly in neutral po-
sition, middle detent, and install interlock sleeve,
ball, poppet spring and interlock pin.
4.
Install remaining poppet ball and then install second
and third shifter shaft and plate assembly.
NOTE: Installation is easiest if shifter shaft
and plate assembly passes over ball in its neu-
tral position.
5.
Check clearance between end of interlock sleeve and
shifter shaft and plate cams when one plate is in
neutral and the other is shifted into gear position.
CHEVROLET CHASSIS SERVICE MANUAL
CLUTCH AND TRANSMISSIONS 7-24
is at the full mark on the dip stick, it is just slightly be-
low the planetary gear unit. If additional oil is added,
bringing the oil level above the full mark, the planetary
unit will run in the oil, foaming and aerating the oil. This
aerated oil carried through the various oil pressure pas-
sages (low servo, reverse servo, clutch apply, converter,
etc.) may cause malfunction of the transmission assem-
bly, resulting in cavitation noise in the converter and
improper band or clutch application. Overheating may
also occur.
If the transmission is found consistently low on oil, a
thorough inspection should be made to find and correct
all external oil leaks.
PERIODIC OIL CHANGE
The transmission oil should be changed periodically as
recommended in Section 0, and whenever transmission is
to be removed from the vehicle for repairs.
1.
Run engine for one minute in neutral prior to chang-
ing.
2.
Be sure vehicle is level or raise from the rear only.
3.
Remove the oil pan drain plug and allow oil to drain
thoroughly into a pan or can.
Replace drain plug and refill with approximately two
quarts of oil specified in Section 0.
NOTE: To refill the transmission, remove dip
stick from oil filler tube and refill transmission
with oil specified in Section 0 using filler tube
and funnel J-4264. Then, after shifting into all
ranges at idle speed to fill all oil passages, the
engine should be run at 800-1000 rpm with the
transmission in Neutral until the oil warms up,
then add oil as required to raise the fluid level
to the full mark on the dip stick. Refill capacity
is approximately 2 qts.
4.
Fig.
1PG - Adjusting Low Band Using J-21848
PERIODIC LOW BAND ADJUSTMENT (Fig. 1PG)
Low band adjustment should be periodically performed
at 12,000 mile intervals, or sooner, as necessary if op-
erating performance indicates low band slippage.
1.
Raise vehicle and place selector lever in neutral.
2.
Remove protective cap from transmission adjusting
screw.
3.
a. On Corvette Models: Drop left exhaust pipe for
clearance.
b.
On Chevelle Models: To gain clearance between
underbody and transmission, it may be necessary
to remove rear mount bolts from crossmember,
and move transmission slightly toward passenger
side of vehicle. .
4.
Loosen adjusting screw lock nut 1/4 turn and hold in
this position with wrench.
5.
Using Special Tool J-21848 adjust band to 70 in. lbs.
and back off four (4) complete turns for a band which
has been in operation for 6,000 miles or more,.or
three (3) turns for one in use less than 6,000 miles.
CAUTION: Be sure to hold the adjusting screw
lock nut at 1/4 turn loose with a wrench during"
the.adjusting procedure.
6. Tighten the adjusting screw lock nut to specified
torque.
CAUTION: The amount of back-off is not an
approximate figure, it must be exact.
MANUAL SHIFT LINKAGE CHECK & ADJUST
(Column Type)
1.
The shift tube and lever assembly must be free in the
mast jacket. See Section 9 for alignment of steering
column assembly if necessary.
2.
To check for proper shift linkage adjustment, lift
the transmission selector lever towards the steering
wheel. Allow the selector lever to be positioned in
drive (D) by the transmission detent.
NOTE: Do not use the indicator pointer as a
reference to position the selected lever. When
performing linkage adjustment, pointer is ad-
justed last.
3.
Release the selector lever. The lever should be in-
hibited from engaging low range unless the lever is
lifted.
4.
Lift the selector lever towards the steering wheel,
and allow the lever to be positioned in neutral (N) by
the transmission detent.
5.
Release the selector lever. The lever should now
be inhibited from engaging reverse range unless the
lever is lifted.
6. A properly adjusted linkage will prevent the selector
lever from moving beyond both the neutral detent, and
the drive detent unless the lever is lifted to pass
over the mechanical stop in the steering column.
7.
In the event that an adjustment is required, place
the selector lever in drive (D) position as determined
by the transmission detent. See Steps 2 and 3.
8. Loosen the adjustment swivel at the cross-shaft,
and rotate the transmission lever so that it contacts
the drive stop in the steering column.
9. Tighten the swivel and recheck the adjustment. See
2 and 6.
CHEVROLET CHASSIS SERVICE MANUAL
CLUTCH AND TRANSMISSIONS
7*30
V-8 Models-With Uni-Directional Linkage
1.
Remove air cleaner.
2.
Disconnect accelerator linkage at carburetor.
3.
Disconnect accelerator return and TV rod return
springs.
4.
With right hand, pull TV upper rod forward until
transmission is through detent. With left hand, open
carburetor to wide open throttle position. Carbure-
tor must reach wide open throttle position at the
same time the ball stud contacts end of slot in upper
TV rod.
5. Adjust swivel on end of upper TV rod to obtain set-
ting described in Step 4. Allowable tolerance is
approximately 1/32".
6. Connect and adjust accelerator linkage as described
in Section 6.
7. Check for throttle linkage freedom.
Neutral Safety Switch Adjustment
The adjustment at the neutral safety switch is de-
scribed in the Electrical Section 12.
Throttle Return Check Valve (Dashpot) Adjustment
The adjustment of the throttle return check valve is
described in Section 6M for each carburetor installation.
Fig.
12PG - Floor Mounted Control Lever and
Bracket Assembly (Chevrolet Shown)
COMPONENT PARTS REPLACEMENT
TRANSMISSION REPLACEMENT (EXC. CORVETTE)
Removal
1.
Raise car on hoist (preferably) or on stand jack and
remove oil pan drain plug to drain oil.
NOTE:
If desired, the oil may be drained after
transmission removal.
2.
Disconnect the oil cooler lines (external cooled
models), vacuum modulator line and the speedometer
drive cable fitting at the transmission. Tie lines
out of the way.
3.
Disconnect manual and TV control lever rods from
transmission.
4.
Disconnect propeller shaft from transmission.
5. Install suitable transmission lift equipment to jack
or other lifting device and attach on transmission.
6. Disconnect engine rear mount on transmission ex-
tension, then disconnect the transmission support
crossmember and slide rearward.
7. Remove converter underpan, scribe flywheel-con-
verter relationship for assembly, then remove the
flywheel-to-converter attaching bolts.
NOTE:
The "light" side of the converter is
denoted by a "blue" stripe painted across the
ends of the converter cover and housing. This
marking should be aligned as closely as possible
with the "white" stripe painted on the. engine
side of the flywheel outer rim (heavy side of
engine) to maintain balance.
8. Support engine at the oil pan rail with a jack or other
suitable brace capable of supporting the engine
weight when the transmission is removed.
9. Lower the rear of the transmission slightly so that
the upper transmission housing-to-engine attaching
bolts can be reached using a universal socket and a
long extension. Remove upper bolts.
CAUTION: Oh V-8 engines, care must be taken
not to lower rear of transmission too far as the
distributor housing may be forced against the
dash causing damage to the distributor. It is
best to have an assistant observe clearance of
all upper engine components while the trans-
mission rear end is being lowered.
10.
Remove remainder of transmission housing-to-
engine attaching bolts.
11.
Remove the transmission by moving it slightly to the
rear and downward, then remove from beneath the
car and transfer to a work bench.
NOTE:
Observe converter when moving the
transmission rearward. If it does not move
with the transmission, pry it free of flywheel
before proceeding.
CAUTION: Keep front of transmission upward
to prevent the converter from falling out. Install
converter Tool J-9549 (or a similar tool con-
structed as shown in Figure 13PG, or, in an
emergency, a length of strong wire may be used)
immediately after removal from the engine.
Installation
NOTE:
The "light" side, of the converter is
denoted by a "blue" stripe painted across the
ends of the converter cover and housing. This
marking should be aligned as closely as possible
CHEVROLET CHASSIS SERVICE MANUAL
CLUTCH AND TRANSMISSIONS 7-32
21.
Remove transmission output shaft slip yoke and in-
sert a plastic shipping plug in end of extension to
prevent spillage of transmission fluid.
NOTE:
The yoke is removed to avoid tearing
the heat reflecting pad on the underbbdy, when
the transmission is being removed.
22.
Remove bright metal ignition shielding from dis-
tributor area.
23.
Remove the transmission dip stick and tube
assembly.
24.
Disconnect transmission vacuum modulator line at
distributor advance line tee.
25.
Position transmission hoist under transmission and
attach safety chain to transmission.
26.
Remove transmission converter housing-to-engine
attaching foolts and slide transmission rearward.
NOTE:
Observe converter when moving trans-
mission rearward. If converter does not move
with the transmission, pry it free of flywheel
before proceeding.
27.
Install converter retaining strap.
28.
Lower and remove transmission from vehicle by
tilting the front down and to the right while inter-
mittently lowering the transmission to facilitate its
• removal.
29.
Reinstall transmission assembly by performing the
above steps in reverse order.
Bolt Torques
Transmission Case to Flywheel
Housing Bolts 35 ft. lbs.
Converter to Flywheel Bolts. . , . . 35 ft. lbs.
OTHER SERVICE OPERATIONS
Although certain operations, such as oil pan or gasket
replacement, valve body, governor, filler pipe "O" ring,
speedometer drive gear, case extension "0" ring and
rear oil seal, vacuum modulator, and servo cover or
gasket service may be performed from underneath the
vehicle without removing the Powerglide; their service
procedure is covered in the Passenger Overhaul Manual
and is not repeated here. Refer to the- Powerglide Sec-
tion of the Passenger Overhaul Manual for all other
service operations not covered here.
DIAGNOSIS
Proper operation of the Powerglide transmission may
be affected by a number of factors, all of which must be
considered when trouble in the unit is diagnosed.
Proper trouble diagnosis can only be accomplished
when performed in a thorough step by step procedure.
The following procedure has been devised and tested and
is recommended for all trouble diagnosis complaints and
if the service man will follow this checking procedure,
accurate and dependable diagnosis may be accomplished.
This will result in a savings of time, not only to the
service man, but to the customer as well.
WARMING UP TRANSMISSION
Before attempting to check and/or correct any com-
plaints on the Powerglide transmission it is absolutely
essential that the oil level be checked and corrected if
necessary. An oil level which is either too high or too
low can be the cause of a number of abnormal conditions
from excessive noise to slippage in all ranges.
It must be remembered that cold oil will slow up the
action of the hydraulic controls in the transmission. For
this reason a trouble or oil leak diagnosis should not be
attempted until the transmission has been warmed up by
either of the following procedures:
Shop Warm Up
1.
Connect tachometer to engine.
2.
Set parking brake tight and start engine.
3.
Place selector light in
"D"
(drive) range.
4.
Adjust carburetor idle speed adjusting screw to run
engine at approximately 750 rpm and operate in this
manner for two minutes. At the end of two minutes
of operation, the transmission will be sufficiently
warmed up for diagnosis purposes.
NOTE:
At this point, readjust the engine idle
speed to 450-475 rpm in
"D"
range.
Road Warm Up
Drive the car approximately 5 miles with frequent
starts and stops.
NOTE:
At this point, make sure the engine idle
speed is set to 450-475 rpm in
"D"
range.
CHECKING FLUID LEVEL AND CONDITION
After transmission has been warmed up, check the
fluid level with the engine idling, parking brake set and
control lever in "N" (neutral). If the fluid level is low,
add fluid to bring level up to the full mark on gauge rod,
CAUTION: If fluid level is too high, fluid may
be aerated by the planet carrier. Aerated fluid
will cause turbulence in the converter which will
result in lost power, lower stall speed and lower
pressures in control circuits. Lower fluid level
to full mark, then shut off engine to allow air
bubbles to work out of fluid.
When checking oil level, aburned smell and discolora-
tion indicate burned clutches or bands and the transmis-
sion will have to be removed.
MANUAL LINKAGE
Manual linkage adjustment and the associated neutral
safety switch are important from a safety standpoint.
The neutral safety switch should be adjusted so that the
engine will start in the Park and Neutral positions only.
With the selector lever in the Park position, the park-
ing pawl should freely engage and prevent the vehicle
CHEVROLET CHASSIS SERVICE MANUAL
CLUTCH AND TRANSMISSIONS 7-33
from rolling. The pointer on the indicator quadrant
should line up properly with the range indicators in all
ranges.
OIL LEAKS
Before attempting to correct an oil leak, the actual
source of the leak must be determined. In many cases
the source of the leak can be deceiving due to "wind flow1 f
around the engine and transmission.
The suspected area should be wiped clean of all oil
before inspecting for the source of the leak. Red dye is
used in the transmission oil at the assembly plant and
will indicate if the oil leak is from the transmission.
The use of a "black light"* to identify the oil at the
source of leak is also helpful. Comparing the oil from
the leak to that on the engine or transmission dip stick
(when viewed by black light) will determine the source
of the leak.
Oil leaks around the engine and transmission are gen-
erally carried toward the rear of the car by the air
stream. For example, a transmission "oil filter tube
to case leak" will sometimes appear as a leak at the
rear of the transmission. In determining the source of
an oil leak it is most helpful to keep the engine running.
The mating surfaces of servo cover, converter housing,
transmission case and transmission case extension
should be carefully examined for signs of leakage. The
vacuum modulator must also be checked to insure that
the diaphragm has not ruptured as this would allow trans-
mission oil to be drawn into the intake manifold. Us-
ually, the exhaust will be excessively smoky if the
diaphragm ruptures due to the transmission oil added to
the combustion. The transmission case extension rear
oil seal should also be checked. All test plugs should be
checked to make sure that they are tight and that there
is no sign of leakage at these points. The converter
underpan should also be removed. Any appreciable quan-
tity of oil in this area would indicate leakage at the pump
square seal ring, pump seal assembly, or pump bolt
sealing washers.
BASIC PRESSURE CHECKS
Four basic pressure checks are used for diagnosis and
operational checks for the Aluminum Powerglide trans-
mission. All checks should be made only after thoroughly
warming up the transmission.
• Wide Open Throttle Upshift Pressure.
• Idle Pressure in "Drive" Range.
• Manual "Low" Range Pressure.
• "Drive" Range Overrun (Coast) Pressure.
It is not recommended that stall tests be conducted
which would result in engine vacuum falling below 10" Hg.
Pressure gauge hose connections should be made at
the low servo apply (main line) test point (fig. 14PG).
Run the gauge line into the driving compartment by
pushing aside the mast jacket seal. The line out of the
way of the drivers feet and connect to pressure gauge
J-21867.
• Wide Open Throttle Upshift Pressure Check
Refer to the pressure check chart for upshift pressure
SERVO APPLY
PRESSURE
Fig.
14PG - Pressure Test Plug
points as indicated on the lower servo apply (main line)
gauge.
• Idle Pressure in "Drive" Range
In addition tp the oil pressure gauges, a vacuum gauge
is needed for this check.
With the parking brake applied and the shift selector
lever in "Drive", low servo apply (main line) pressure
should be as shown on the pressure check chart.
If pressures are not within these ranges, the following
items should be checked for oil circuit leakage:
1.
Pressure regulator valve stuck.
2.
Vacuum modulator valve stuck.
3.
Hydraulic modulator valve stuck.
4.
Leak at low servo piston ring (between ring and
bore).
5.
Leak at low servo piston rod (between rod and bore).
6. Leak at valve body to case gasket.
7.
Leak at valve body gaskets.
8. Front pump clearances.
9. Check passages in transmission case for porosity.
• Manual "Low" Range Pressure Check
Connect a tachometer, apply the parking brake, place
the selector lever in "Low" range, and adjust the engine
speed to 1000 rpm with the car stationary.
Low servo apply (main line) pressure should be as
shown on the pressure check chart.
Pressures not within this range can indicate the fol-
lowing possibilities:
1.
Partially plugged oil suction screen.
2.
Broken or damaged ring low servo.
CHEVROLET CHASSIS SERVICE MANUAL
CLUTCH AND TRANSMISSIONS 7-37
LI.
- LI Range can be selected at any vehicle speed,
and the transmission will shift to second gear
and remain in second until vehicle speed is re-
duced to approximately 40 MPH, .depending on
axle ratio. LI Range position prevents the trans-
mission from shifting out of first gear.
It is very important that any communication concerning
the Turbo Hydra-Matic always contain the transmission
serial number and that all transmission parts returned
to Chevrolet Motor Division always be tagged with the
transmission serial number.
MAINTENANCE AND ADJUSTMENTS
TRANSMISSION FLUID
Transmission fluid level should be checked with trans-
mission warm and selector lever in "P" Park position,
every time engine oil level is checked or as specified in
Section 0 when engine oil is changed.
CAUTION: Since the Turbo Hydra-Matic trans-
mission is very sensitive to oil level, special
precautions should be taken when checking the
oil level, to insure against an overfifE
Transmission fluid should be changed as specified in
Section 0.
FLUID LEVEL INDICATOR
The fluid level indicator is located in the filler pipe at
the right rear corner of the engine. To bring the fluid
level from the add mark to the full mark add 1 pint.
Fluid level should be to the full mark with transmission
at normal operating temperature. With cold fluid the
level should be at the add mark or slightly below.
SHIFT CONTROL LINKAGE ADJUSTMENT
Adjust linkage as shown below and in Figure 2.
1.
The shift tube and lever assembly must be free in the
mast jacket See Section 9 for alignment of steering
column assembly if necessary.
2.
To check for proper shift linkage adjustment, lift the
transmission selector lever towards the steering
wheel. Allow the selector lever to be positioned in
drive (D) by the transmission detent.
NOTE: Do not use the indicator pointer as a
reference to position the selector lever. When
performing linkage adjustment, pointer is ad-
justed last.
3.
Release the selector lever. The lever should be in-
hibited from engaging low range unless the lever is
lifted.
4.
Lift the selector lever towards the steering wheel,
and allow the lever to be positioned in neutral (N) by
the transmission detent.
5.
Release the selector lever. The lever should now be
inhibited from engaging reverse range unless the
lever is lifted.
6. A properly adjusted linkage will prevent the selector
lever from moving beyond both the neutral detent,
and the drive detent unless the lever is lifted to pass
over the mechanical stop in the steering column.
See schematic diagram.
7.
In the event that an adjustment is required, place the
selector lever in drive (D) position as determined by
the transmission detent. See Steps 2 and 3.
8. Loosen the adjustment swivel at the cross-shaft, and
rotate the transmission lever so that it contacts the
drive stop in the steering column.
9. Tighten the swivel and recheck the adjustment. See
Steps 2 and 6. -
l(h Readjust indicator needle if necessary to agree with
the transmission detent" positions. See Section 9.
11.
Readjust neutral safety switch if necessary to pro-
vide the correct relationship to the transmission de-
tent positions. See Section 12.
12.
When properly adjusted the following conditions must
be met by manual operation of the steering column
shift lever:
a. From reverse to drive position travel, the trans-
mission detent feel must be noted and related to
indicated position on dial.
b.
When in drive and reverse positions, pull lever
rearward (towards steering wheel) and then re-
lease. It must drop back into position with no
restrictions.
NEUTRAL SAFETY SWITCH ADJUSTMENT
The neutral safety switch must be adjusted so that the
car will start in the park or neutral position, but will not
start in the other positions. For replacement refer to
Section 12 of this Manual.
DRAINING AND REFILLING TRANSMISSION
Drain oil immediately after operation before it has had
an opportunity to cool.
To drain oil proceed as follows:
1.
Remove bottom pan attaching screws, pan, and gas-
ket.
2.
Remove oil strainer. Remove "O" ring seal from
pick-up pipe and discard.
3.
Discard strainer if dirty.
4.
Install new "O" ring seal on pick-up pipe and install
strainer and pipe assembly.
5.
Thoroughly clean bottom pan.
6.. Affix new gasket to bottom pan with petroleum jelly.
7.
Install bottom pan with attaching screws and torque
to specifications;
8. If only the pan has been removed, pour approximately
7-1/2 pints of fluid into the transmission. If the
valve body has also been removed use 9-1/2 pints.
After a complete overhaul approximately 19 pints
are required. Be sure container, spout, or funnel is
clean.
9. Start engine and let idle (carburetor off fast idle
step).
Place selector lever in P position and apply
hand brake.
10.
With transmission warm (approximately 150°F), add
fluid to bring level to full mark on indicator.
CAUTION: Do not overfill. Foaming will re-
sult.
CHEVROLET CHASSIS SERVICE MANUAL
CLUTCH AND TRANSMISSIONS 7-41
CAUTION: Use converter holding ToolJ-5384
when lowering transmission or keep rear of
transmission lower than front so as not to lose
converter.
The installation of the transmission is the reverse of
the removal.
TURBO HYDRA-MATIC DIAGNOSIS PROCEDURE
Accurate diagnosis of transmission problems begins
with a thorough understanding of normal transmission
operation. In particular, knowing which units are in-
volved in the various speeds or shifts so that the specific
units or circuits involved in the problem can be isolated
and investigated further. Analytical diagnosis will pro-
tect the technician from come backs and certainly will
improve owner satisfaction.
An important and often overlooked aspect of diagnosis
is finding out specifically what the customer is com-
plaining of. For this purpose a short ride with the cus-
tomer will often prove beneficial. It may be found that
the condition the customer wants corrected is standard
and should not be altered.
The following sequence, based on field experience, pro-
vides the desired information quickly and in most cases
actually corrects the malfunction without requiring the
removal of the transmission. Details of the items listed
in this sequence are covered further in the text.
SEQUENCE FOR TURBO HYDRA-MATIC
DIAGNOSIS PROCEDURE
1.
Check oil level and condition.
2.
Check and correct detent switch.
3.
Check and correct vacuum line and fittings.
4.
Check and correct manual linkage.
OIL LEVEL AND CONDITION CHECK
Always check the oil level before road testing. Oil
must be visible on dip stick prior to operating the ve-
hicle. Erratic shifting, pump noise, or other malfunc-
tions can in some cases be traced to improper oil level.
Oil level should be checked with the selector lever in
the Park (P) position, engine running, and the vehicle on
level pavement.
Fluid level should be to the FULL mark with the trans-
mission at normal operating temperature (170°-190°
F.).
With warm fluid (room temperature), the level should be
at or slightly below the ADD mark.
If oil level was low, refer to Oil Leaks.
The condition of the oil is often an indication of whether
the transmission should be removed from the vehicle, or
to make further tests. When checking oil level, a burned
smell and discoloration indicate burned clutches or bands
and the transmission will have to be removed.
MANUAL LINKAGE
Manual linkage adjustment and the associated neutral
safety switch are important from a safety standpoint
The neutral safety switch should be adjusted so that the
engine will start in the Park and Neutral positions only.
With the selector lever in the Park position, the park-
ing pawl should freely engage and prevent the vehicle
from rolling. The pointer on the indicator quadrant
should line up properly with the range indicators in all
ranges.
OIL LEAKS
Before attempting to correct an oil leak, the actual
source of the leak must be determined. In many cases,
the source of the leak can be deceiving due to "wind flow"
around the engine and transmission.
The suspected area should be wiped clean of all oil be-
fore inspecting for the source of the leak. Red dye is
used in the transmission oil at the assembly plant and
will indicate if the oil leak is from the transmission.
. The use of a "black light"* to identify the oil at the
source of leak is also helpful. Comparing the oil from
the leak to that on the engine or transmission dip stick
(when viewed by black light) will determine the source
of the leak.
Oil leaks around the engine and transmission are gen-
erally carried toward the rear of the car by the air
stream. For example, a transmission "oil filler tube to
case leak" will sometimes appear as a leak at the rear of
the transmission. In determining the source of an oil
leak it is most helpful to keep the engine running.
POSSIBLE POINTS OF OIL LEAKS
• 1. TRANSMISSION OIL PAN LEAK
a. Attaching bolts not correctly torqued.
b.
Improperly installed or damaged pan gasket.
c. Oil pan gasket mounting face not flat.
2.
REAR EXTENSION LEAK
a. Attaching bolts not correctly torqued.
b.
Rear seal assembly — damaged or improperly
installed.
c. Gasket seal — (extension to case) damaged or
improperly installed.
d. Porous casting.
3.
CASE LEAK
a. Filler pipe "O" ring seal damaged or missing;
misposition of filler pipe bracket to engine —
"loading" one side of
"O"
ring.
b.
Modulator assembly "O" ring seal
—
damaged or
improperly installed.
c. Governor cover, gasket and bolts — damaged,
loose; case face leak.
d. Speedo gear
—
"O" ring damaged.
e. Manual shaft seal — damaged, improperly in-
stalled.
f. line pressure tap plug — stripped, shy sealer
compound.
g. Parking pawl shaft cup plug
—
damaged, improp-
erly installed.
h. Vent pipe (refer to Item 5).
i. Porous case.
4.
FRONT END LEAK
a. Front seal - damaged (check converter neck for
nicks,
etc., also for pump bushing moved for-
ward);
garter spring missing from pump to con-
verter seaL
b.
Pump attaching bolts and seals
—
damaged, miss-
ing, bolts loose.
CHEVROLET a
SERVICE
FUEL TANK AND EXHAUST SYSTEMS 8-2
COMPONENT PART REPLACEMENT
FUEL TANK
Draining Tank
The absence of a drain plug in the gas tanks makes it
necessary to siphon fuel from the tank when draining is
needed. The following procedure is recommended.
1.
Obtain approximately 10 feet of 3/8" I.D. hose and
cut a flat-type slit 18" from one end. Make this cut
on the hose in the direction "toward the shorter end
(See Figure 2).
2.
Insert a small pipe nipple (slightly larger O.D. than
the hose I.D.) into the opposite end of hose.
3.
Insert the nipple end of the siphon hose into the fuel
tank filler neck with the natural curl of the hose
pointing down. Insert until the hose is heard to strike
bottom of the tank.
4.
With the opposite end of the hose in a suitable con-
taner insert an air hose in downward direction in the
flap-type slit and trigger the flow of fuel.
FUEL FLOW
-If*
APPROX.-1 >SUT «<>«
AS SHOWN
10 FEET APPROX.-
Fig. 2—Siphon Construction
FWD
V-8
VIEW B
Fig. 3-Fuel Lines
CHEVROLET CHASSIS SERVICE MANUAL