weight DODGE RAM 2001 Service Workshop Manual

NOTE: Worn valve guides or cocked springs are
sometimes mistaken for noisy tappets. If such is the
case, noise may be dampened by applying side thrust
on the valve spring. If noise is not appreciably
reduced, it can be assumed the noise is in the tappet.
Inspect the rocker arm push rod sockets and push rod
ends for wear.
(3)Valve tappet noise ranges from light noise to a
heavy click. A light noise is usually caused by excessive
leak-down around the unit plunger, or by the plunger
partially sticking in the tappet body cylinder. The tap-
pet should be replaced. A heavy click is caused by a tap-
pet check valve not seating, or by foreign particles
wedged between the plunger and the tappet body. This
will cause the plunger to stick in the down position.
This heavy click will be accompanied by excessive clear-
ance between the valve stem and rocker arm as valve
closes. In either case, tappet assembly should be
removed for inspection and cleaning.
(4) The valve train generates a noise very much
like a light tappet noise during normal operation.
Care must be taken to ensure that tappets are mak-
ing the noise. If more than one tappet seems to be
noisy, it's probably not the tappets.
LEAK-DOWN TEST
After cleaning and inspection, test each tappet for
specified leak-down rate tolerance to ensure zero-lash
operation (Fig. 36).
Swing the weighted arm of the hydraulic valve tap-
pet tester away from the ram of the Universal Leak-
Down Tester.
(1)
Place a 7.925-7.950 mm (0.312-0.313 inch) diame-
ter ball bearing on the plunger cap of the tappet.
(2) Lift the ram and position the tappet (with the
ball bearing) inside the tester cup.
(3) Lower the ram, then adjust the nose of the ram
until it contacts the ball bearing. DO NOT tighten
the hex nut on the ram.
(4) Fill the tester cup with hydraulic valve tappet
test oil until the tappet is completely submerged.
(5) Swing the weighted arm onto the push rod and
pump the tappet plunger up and down to remove air.
When the air bubbles cease, swing the weighted arm
away and allow the plunger to rise to the normal
position.
(6) Adjust the nose of the ram to align the pointer
with the SET mark on the scale of the tester and
tighten the hex nut.
(7)
Slowly swing the weighted arm onto the push rod.
(8)Rotate the cup by turning the handle at the base
of the tester clockwise one revolution every 2 seconds.
(9) Observe the leak-down time interval from the
instant the pointer aligns with the START mark on
the scale until the pointer aligns with the 0.125
mark. A normally functioning tappet will require20-110 seconds to leak-down. Discard tappets with
leak-down time interval not within this specification.
REMOVAL
(1)Remove the air cleaner assembly and air in-let
hose.
(2) Remove cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(3) Remove rocker assembly and push rods. Iden-
tify push rods to ensure installation in original loca-
tions.
(4) Remove intake manifold (Refer to 9 - ENGINE/
MANIFOLDS/INTAKE MANIFOLD - REMOVAL).
(5) Remove yoke retainer and aligning yokes.
(6) Slide Hydraulic Tappet Remover/Installer Tool
C-4129-A through opening in cylinder head and seat
tool firmly in the head of tappet.
(7) Pull tappet out of bore with a twisting motion.
If all tappets are to be removed, identify tappets to
ensure installation in original location.
(8) If the tappet or bore in cylinder block is scored,
scuffed, or shows signs of sticking, ream the bore to
next oversize. Replace with oversize tappet.
CLEANING
Clean tappet with a suitable solvent. Rinse in hot
water and blow dry with a clean shop rag or com-
pressed air.
INSTALLATION
(1) Lubricate tappets.
Fig. 36 Leak-Down Tester
1 - POINTER
2 - WEIGHTED ARM
3 - RAM
4 - CUP
5 - HANDLE
6 - PUSH ROD
9 - 152 ENGINE 5.9LBR/BE
HYDRAULIC LIFTERS (Continued)

(2) Install tappets and push rods in their original
positions. Ensure that the oil feed hole in the side of
the tappet body faces up (away from the crankshaft).
(3) Install aligning yokes with ARROW toward
camshaft.
(4) Install yoke retainer. Tighten the bolts to 23
N´m (200 in. lbs.) torque. Install intake manifold
(Refer to 9 - ENGINE/MANIFOLDS/INTAKE MANI-
FOLD - INSTALLATION).
(5) Install push rods in original positions.
(6) Install rocker arms.
(7) Install cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
(8) Install air cleaner assembly and air in-let hose.
(9) Start and operate engine. Warm up to normal
operating temperature.
CAUTION: To prevent damage to valve mechanism,
engine must not be run above fast idle until all
hydraulic tappets have filled with oil and have
become quiet.
PISTON & CONNECTING ROD
DESCRIPTION
The pistons are made of aluminum and have three
ring grooves, the top two grooves are for the compres-
sion rings and the bottom groove is for the oil control
ring. The connecting rods are forged steel and are
coined prior to heat treat. The piston pins are press fit.
STANDARD PROCEDUREÐPISTON FITTING
Piston and cylinder wall must be clean and dry.
Specified clearance between the piston and the cylin-
der wall is 0.013-0.038 mm (0.0005-0.0015 inch) at
21ÉC (70ÉF).
Piston diameter should be measured at the top of
skirt, 90É to piston pin axis. Cylinder bores should be
measured halfway down the cylinder bore and trans-
verse to the engine crankshaft center line.
Pistons and cylinder bores should be measured at
normal room temperature, 21ÉC (70ÉF).
Check the pistons for taper and elliptical shape
before they are fitted into the cylinder bore (Fig. 37).
PISTON MEASUREMENT CHART
PISTON A DIA = PISTON BORE
SIZE DIAMETER DIAMETER
MIN. MAX. MIN. MAX.
mm
(in.)mm
(in.)mm
(in.)mm (in.)
AÐÐÐ Ð
B101.580 101.592 101.605 101.618
(3.9992) (3.9997) (4.0002) (4.0007)
C101.592 101.605 101.618 101.630
(3.9997) (4.0002) (4.0007) (4.0012)
D101.605 101.618 101.630 101.643
(4.0002) (4.0007) (4.0012) (4.0017)
EÐÐÐ Ð
DESCRIPTION SPECIFICATION
PISTON PIN BORE 25.007 - 25.015 mm
(.9845 - .9848 in.)
RING GROOVE
HEIGHT
OIL RAIL 4.033 - 4.058 mm
(.1588 - .1598 in.)
COMPRESSION
RAIL1.529 - 1.554 mm
(.0602 - .0612 in.)
TOTAL FINISHED 470.8   2 grams
WEIGHT (16.607   .0706 ounces)
Fig. 37 Piston Measurements
1 - 49.53 mm (1.95 IN.)
BR/BEENGINE 5.9L 9 - 153
HYDRAULIC LIFTERS (Continued)

LUBRICATION
DESCRIPTION..........................214
OPERATION............................214
DIAGNOSIS AND TESTING................215
ENGINE OIL LEAKS....................215
ENGINE OIL PRESSURE................215
OIL
STANDARD PROCEDURE.................217
ENGINE OIL..........................217
OIL FILTER
REMOVAL.............................218
INSTALLATION..........................218
OIL PAN
REMOVAL.............................218
CLEANING.............................218
INSPECTION...........................219
INSTALLATION..........................219
OIL PUMP
REMOVAL.............................219
CLEANING.............................220
INSPECTION...........................220
INSTALLATION..........................221INTAKE MANIFOLD
DESCRIPTION..........................222
DIAGNOSIS AND TESTING................222
INTAKE MANIFOLD LEAKAGE............222
REMOVAL.............................222
CLEANING.............................223
INSPECTION...........................223
INSTALLATION..........................223
EXHAUST MANIFOLD
DESCRIPTION..........................224
OPERATION............................224
REMOVAL.............................225
CLEANING.............................225
INSPECTION...........................225
INSTALLATION..........................225
TIMING BELT / CHAIN COVER(S)
REMOVAL.............................225
INSTALLATION..........................226
TIMING BELT/CHAIN AND SPROCKETS
REMOVAL.............................226
INSPECTION...........................227
INSTALLATION..........................227
ENGINE 8.0L
DESCRIPTION
The 8.0 Liter (488 CID) ten-cylinder engine is a
V-Type lightweight, single cam, overhead valveengine with hydraulic roller tappets. This engine is
designed for unleaded fuel.
Engine lubrication system consists of a gerotor type
oil pump mounted in the timing chain cover and driven
by the crankshaft. The V-10 uses a full flow oil filter.
The cylinders are numbered from front to rear; 1, 3,
5, 7, 9 on the left bank and 2, 4, 6, 8, 10 on the right
bank. The firing order is 1-10-9-4-3-6-5-8-7-2 (Fig. 1).
The engine serial number is located on the lower
left front of the cylinder block in front of the engine
mount (Fig. 2). When component part replacement is
necessary, use the engine type and serial number for
reference.
Fig. 1 Firing Order
Fig. 2 Engine IdentificationÐ(Serial Number)
1 - ENGINE SERIAL NO.
2 - ENGINE MOUNT LOCATION
9 - 172 ENGINE 8.0LBR/BE

SPECIFICATIONS
8.OL ENGINE
DESCRIPTION SPECIFICATION
CAMSHAFT
Bearing Diameter
No. 1 53.16 ± 53.19 mm
(2.093 ± 2.094 in.)
No. 2 52.76 ± 52.78 mm
(2.077 ± 2.078 in.)
No. 3 52.35 ± 52.37 mm
No. 4 51.94 ± 51.97 mm
(2.045 ± 2.046 in.)
No. 5 51.54 ± 51.56 mm
(2.029 ± 2.030 in.)
No. 6 48.74 ± 48.77 mm
(1.919 ± 1.920 in.)
Bearing Journal Diameter
No. 1 53.11 ± 53.14 mm
(2.091 ± 2.092 in.)
No. 2 52.69 ± 52.72 mm
(2.0745 ± 2.0755 in.)
No. 3 52.30 ± 52.32 mm
(2.059 ± 2.060 in.)
No. 4 51.89 ± 51.92 mm
(2.043 ± 2.044 in.)
No. 5 51.49 ± 51.51 mm
(2.027 ± 2.028 in.)
No. 6 48.69 ± 48.72 mm
(1.917 ± 1.918 in.)
Bearing to Journal
Clearance
No. 1,3,4,5,6 0.0254 ± 0.0762 mm
(0.001 ± 0.003 in.)
No. 2 0.0381 ± 0.0889 mm
(0.0005 ± 0.0035 in.)
Service Limit 0.127 mm (0.005 in.)
End Play 0.127 ± 0.381 mm
(0.005 ± 0.015 in.)
DESCRIPTION SPECIFICATION
CONNECTING RODS
Piston Pin bore Diameter 24.940 ± 24.978 mm
(0.9819 ± 0.9834 in.)
Side Clearance 0.25 ± 0.46 mm
(0.010 ± 0.018 in.)
Total Weight (Less
Bearing)744 gms. (26.24 oz.)
CRANKSHAFT
Rod Journal Diameter 53.950 ± 53.975 mm
(2.124 ± 2.125 in.)
Out of Round (Max.) 0.0254 mm (0.001 in.)
Taper (Max.) 0.0254 mm (0.001 in.)
Bearing Clearance 0.005 ± 0.074 mm
(0.0002 ± 0.0029 in.)
Service Limit 0.0762 mm (0.003 in.)
Main Bearing Journal
Diameter76.187 ± 76.213 mm
(2.8995 ± 3.0005 in.)
Out of Round (Max.) 0.0254 mm (0.001 in.)
Taper (Max.) 0.0254 mm (0.001 in.)
Bearing Clearance 0.0051 ± 0.058 mm
(0.0002 ± 0.0023 in.)
Service Limit 0.071 mm (0.0028 in.)
End Play 0.076 ± 0.305 mm
(0.003 ± 0.012 in.)
Service LimitÐEnd Play 0.381 mm (0.015 in.)
CYLINDER BLOCK
Cylinder Bore Diameter 101.60 ± 101.65 mm
(4.0003 ± 4.0008 in.)
Out of Round (Max.) 0.0762 mm (0.003 in.)
Taper (Max.) 0.127 mm (0.005 in.)
Lifter Bore Diameter 22.982 ± 23.010 mm
(0.9048 ± 0.9059 in.)
9 - 184 ENGINE 8.0LBR/BE
ENGINE 8.0L (Continued)

DESCRIPTION SPECIFICATION
Weight 463 ± 473 grams (16.33
± 16.68 oz.)
Piston to Bore Clearance 0.013 ± 0.038 mm
(0.0005 ± 0.0015 in.)
Service Limit 0.0762 mm (0.003 in.)
PISTON PINS
Clearance in Piston 0.010 ± 0.020 mm
(0.0004 ± 0.0008 in.)
Diameter 24.996 ± 25.001 mm
(0.9841 ± 0.9843 in.)
End Play NONE
Length 67.8 ± 68.3 mm
(2.67 ± 2.69 in.)
PISTON RINGS
Ring Gap
Compression Rings 0.254 ± 0.508 mm
(0.010 ± 0.020 in.)
Oil Control (Steel Rails) 0.381 ± 1.397 mm
(0.015 ± 0.055 in.)
Ring Side Clearance
Compression Rings 0.074 ± 0.097 mm
(0.0029 ± 0.0038 in.)
Oil Ring (Steel Rails) 2.591 ± 2.743 mm
(0.102 ± 0.108 in.)
VALVE TIMING
Exhaust Valve
Closes (ATDC) 25É
Opens (BBDC) 60É
Duration 265É
Intake Valve
Closes (ATDC) 61É
Opens (BBDC) 6É
Duration 246É
Valve Overlap 31ÉCRANKSHAFT JOURNAL MARKING
LOCATION
MEASURE-
MENTITEM IDENTIFI-
CATIONLOCATION
OF
IDENTIFI-
CATION
0.0254 mm
(0.001 in.)
U/SCrankshaft
JournalsRorM
M-2-3 ect.
(indicating
No. 2 and
3 main
bearing
journal)
and/or
R-1-4 ect.
(indicating
No. 1 and
4
connecting
rod
journal)Milled flat
on No. 8
crankshaft
counter-
weight.
0.508 mm
(0.020 in.)
O/SCylinder
BoresA Following
engine
serial
number.
0.2032 mm
(0.008 in.)
O/SHydraulic
TappetsLDiamond-
shaped
stamp top
pad - front
of engine
and flat
ground on
outside
surface of
each O/S
tappet
bore.
0.127 mm
(0.005 in.)Valve
StemsX Milled pad
adjacent to
two tapped
holes 3/89
on each
end of
cylinder
head.
9 - 186 ENGINE 8.0LBR/BE
ENGINE 8.0L (Continued)

NOTE: Worn valve guides or cocked springs are
sometimes mistaken for noisy tappets. If such is
the case, noise may be dampened by applying side
thrust on the valve spring. If noise is not apprecia-
bly reduced, it can be assumed the noise is in the
tappet. Inspect the rocker arm push rod sockets
and push rod ends for wear.
(3) Valve tappet noise ranges from light noise to a
heavy click. A light noise is usually caused by exces-
sive leak-down around the unit plunger, or by the
plunger partially sticking in the tappet body cylinder.
The tappet should be replaced. A heavy click is
caused by a tappet check valve not seating, or by for-
eign particles wedged between the plunger and the
tappet body. This will cause the plunger to stick in
the down position. This heavy click will be accompa-
nied by excessive clearance between the valve stem
and rocker arm as valve closes. In either case, tappet
assembly should be removed for inspection and clean-
ing.
(4) The valve train generates a noise very much
like a light tappet noise during normal operation.
Care must be taken to ensure that tappets are mak-
ing the noise. If more than one tappet seems to be
noisy, it's probably not the tappets.
LEAK-DOWN TEST
After cleaning and inspection, test each tappet for
specified leak-down rate tolerance to ensure zero-lash
operation (Fig. 36).
Swing the weighted arm of the hydraulic valve tap-
pet tester away from the ram of the Universal Leak-
Down Tester.
(1) Place a 7.925-7.950 mm (0.312-0.313 inch)
diameter ball bearing on the plunger cap of the tap-
pet.
(2) Lift the ram and position the tappet (with the
ball bearing) inside the tester cup.
(3) Lower the ram, then adjust the nose of the ram
until it contacts the ball bearing. DO NOT tighten
the hex nut on the ram.
(4) Fill the tester cup with hydraulic valve tappet
test oil until the tappet is completely submerged.
(5) Swing the weighted arm onto the push rod and
pump the tappet plunger up and down to remove air.
When the air bubbles cease, swing the weighted arm
away and allow the plunger to rise to the normal
position.
(6) Adjust the nose of the ram to align the pointer
with the SET mark on the scale of the tester and
tighten the hex nut.
(7) Slowly swing the weighted arm onto the push
rod.
(8) Rotate the cup by turning the handle at the
base of the tester clockwise one revolution every 2
seconds.(9) Observe the leak-down time interval from the
instant the pointer aligns with the START mark on
the scale until the pointer aligns with the 0.125
mark. A normally functioning tappet will require
20-110 seconds to leak-down. Discard tappets with
leak-down time interval not within this specification.
REMOVAL
(1) Disconnect the negative cable from the battery.
(2) Remove the air cleaner.
(3) Remove cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - REMOVAL).
(4) Remove rocker arm assembly and push rods
(Refer to 9 - ENGINE/CYLINDER HEAD/ROCKER
ARM / ADJUSTER ASSY - REMOVAL). Identify
push rods to ensure installation in original location.
(5) Remove upper and lower intake manifold
(Refer to 9 - ENGINE/MANIFOLDS/INTAKE MANI-
FOLD - REMOVAL).
(6) Cut the cylinder head gasket for accessibility if
the end tappets are to be removed.
(7) Remove yoke retainer spider and tappet align-
ing yokes (Fig. 37).
(8) Pull tappet out of bore with a twisting motion.
If all tappets are to be removed, identify tappets to
ensure installation in original location.
(9) If the tappet or bore in cylinder block is scored,
scuffed, or shows signs of sticking, ream the bore to
next oversize. Replace with oversize tappet.
(10) Check camshaft lobes for abnormal wear.
Fig. 36 Leak-Down Tester
1 - POINTER
2 - WEIGHTED ARM
3 - RAM
4 - CUP
5 - HANDLE
6 - PUSH ROD
BR/BEENGINE 8.0L 9 - 207
HYDRAULIC LIFTERS (Continued)

CLEANING
Clean tappet with a suitable solvent. Rinse in hot
water and blow dry with a clean shop rag or com-
pressed air.
INSTALLATION
(1) Lubricate tappets.
(2) Install tappets in their original positions.
Ensure that the oil bleed hole (if so equipped)
faces forward.
(3) Install tappet aligning yokes. Position the yoke
retainer spider over the tappet aligning yokes (Fig.
37)Install the yoke retaining spider bolts and tighten
to 22 N´m (16 ft. lbs.) torque.
(4) Install the push rods in their original location.
(5) Install the rocker arms (Refer to 9 - ENGINE/
CYLINDER HEAD/ROCKER ARM / ADJUSTER
ASSY - INSTALLATION).
(6) Install lower and upper intake manifold (Refer
to 9 - ENGINE/MANIFOLDS/INTAKE MANIFOLD -
INSTALLATION).
(7) The cylinder head cover gasket can be used
again. Install the gasket onto the head rail.For the
left side the number tab is at the front of
engine with the number up. For the right side
the number tab is at the rear of engine with the
number up.(8) Install cylinder head cover (Refer to 9 -
ENGINE/CYLINDER HEAD/CYLINDER HEAD
COVER(S) - INSTALLATION).
(9) Install the air cleaner.
CAUTION: To prevent damage to valve mechanism,
engine must not be run above fast idle until all
hydraulic tappets have filled with oil and have
become quiet.
(10) Connect the negative cable to the battery.
(11) Road test vehicle and check for leaks.
PISTON & CONNECTING ROD
DESCRIPTION
The pistons (Fig. 38) are elliptically turned so that
the diameter at the pin boss is less than its diameter
across the thrust face. This allows for expansion
under normal operating conditions. Under operating
temperatures, expansion forces the pin bosses away
from each other, causing the piston to assume a more
nearly round shape.
All pistons are machined to the same weight,
regardless of size, to maintain piston balance.
The piston pin rotates in the piston only and is
retained by the press interference fit of the piston
pin in the connecting rod.
The pistons have a unique dry-film lubricant coat-
ing baked onto the skirts to reduce friction. The
lubricant is particularly effective during engine
break-in, but with time, the material becomes embed-
ded into cylinder bore walls and continues to reduce
friction.
The pistons are LH and RH bank specific.
STANDARD PROCEDUREÐPISTON FITTING
Piston and cylinder wall must be clean and dry.
Specified clearance between the piston and the cylin-
der wall is 0.013-0.038 mm (0.0005-0.0015 inch). The
max. allowable clearance is 0.0762 mm (0.003 in.).
Piston diameter should be measured at the top of
skirt, 90É to piston pin axis. Cylinder bores should be
measured halfway down the cylinder bore and trans-
verse to the engine crankshaft center line.
Pistons and cylinder bores should be measured at
normal room temperature, 21ÉC (70ÉF).
(1) To correctly select the proper size piston, a cyl-
inder bore gauge, capable of reading in.00019INCRE-
MENTS is required (Fig. 39). If a bore gauge is not
available, do not use an inside micrometer.The coat-
ing material is applied to the piston after the final
piston machining process. Measuring the outside
diameter of a coated piston will not provide accurate
results. Therefore measuring the inside diameter of
the cylinder bore with a dial Bore Gauge isMANDA-
Fig. 37 Tappets, Aligning Yoke and Yoke Retaining
Spider
1 - TAPPET ALIGNING YOLK
2 - YOKE RETAINING SPIDER
3 - TAPPET
9 - 208 ENGINE 8.0LBR/BE
HYDRAULIC LIFTERS (Continued)

(13) Loosen front band adjusting screw locknut 4-5
turns. Then tighten band adjusting screw until band
is tight around front clutch retainer. This prevents
front/rear clutches from coming out with pump and
possibly damaging clutch or pump components.
(14) Remove oil pump bolts.
(15) Thread bolts of Slide Hammer Tools C-3752
into threaded holes in pump body flange (Fig. 21).
(16) Bump slide hammer weights outward to
remove pump and reaction shaft support assembly
from case (Fig. 21).
(17) Loosen front band adjusting screw until band
is completely loose.
(18) Squeeze front band together and remove band
strut (Fig. 22).
(19) Remove front band lever (Fig. 23).
(20) Remove front band lever shaft plug, if neces-
sary, from converter housing.
(21) Remove front band lever shaft.
Fig. 21 Removing Oil Pump And Reaction Shaft
Support Assembly
1 - OIL PUMP AND REACTION SHAFT SUPPORT ASSEMBLY
2 - SLIDE HAMMER TOOLS C-3752
Fig. 22 Removing Front Band Strut
1 - BAND LEVER
2 - BAND STRUT
3 - FRONT BAND
Fig. 23 Removing Front Band Lever
1 - FRONT BAND LEVER
21 - 162 AUTOMATIC TRANSMISSION - 42REBR/BE
AUTOMATIC TRANSMISSION - 42RE (Continued)

(2) Install the overdrive off switch into the connec-
tor (Fig. 117)
(3) Push the overdrive off switch and wiring into
the shift lever.
(4) Install the overdrive off switch retainer onto
the shift lever.
OVERDRIVE UNIT
REMOVAL
(1) Shift transmission into PARK.
(2) Raise vehicle.
(3) Remove transfer case, if equipped.
(4) Mark propeller shaft universal joint(s) and axle
pinion yoke, or the companion flange and flange
yoke, for alignment reference at installation, if necc-
esary.
(5) Disconnect and remove the rear propeller shaft,
if necessary. (Refer to 3 - DIFFERENTIAL & DRIV-
ELINE/PROPELLER SHAFT/PROPELLER SHAFT -
REMOVAL)
(6) Remove transmission oil pan, remove gasket,
drain oil and reinstall pan.
(7) If overdrive unit had malfunctioned, or if fluid
is contaminated, remove entire transmission. If diag-
nosis indicated overdrive problems only, remove just
the overdrive unit.(8) Support transmission with transmission jack.
(9) Remove bolts attaching overdrive unit to trans-
mission (Fig. 118).
CAUTION: Support the overdrive unit with a jack
before moving it rearward. This is necessary to pre-
vent damaging the intermediate shaft. Do not allow
the shaft to support the entire weight of the over-
drive unit.
(10) Carefully work overdrive unit off intermediate
shaft. Do not tilt unit during removal. Keep it as
level as possible.
(11) If overdrive unit does not require service,
immediately insert Alignment Tool 6227-2 in splines
of planetary gear and overrunning clutch to prevent
splines from rotating out of alignment. If misalign-
ment occurs, overdrive unit will have to be disassem-
bled in order to realign splines.
(12) Remove and retain overdrive piston thrust
bearing. Bearing may remain on piston or in clutch
hub during removal.
(13) Position drain pan on workbench.
(14) Place overdrive unit over drain pan. Tilt unit
to drain residual fluid from case.
(15) Examine fluid for clutch material or metal
fragments. If fluid contains these items, overhaul will
be necessary.
(16) If overdrive unit does not require any service,
leave alignment tool in position. Tool will prevent
accidental misalignment of planetary gear and over-
running clutch splines.
Fig. 117 Install the Overdrive Off Switch
1 - GEAR SHIFT LEVER
2 - OVERDRIVE OFF SWITCH WIRING CONNECTOR
3 - OVERDRIVE OFF SWITCH
Fig. 118 Overdrive Unit Bolts
1 - OVERDRIVE UNIT
2 - ATTACHING BOLTS (7)
21 - 216 AUTOMATIC TRANSMISSION - 42REBR/BE
OVERDRIVE OFF SWITCH (Continued)

The pressure created in the fluid is equal to the force
applied, divided by the piston area. If the force is 100
lbs., and the piston area is 10 sq. in., then the pres-
sure created equals 10 PSI. Another interpretation of
Pascal's Law is that regardless of container shape or
size, the pressure will be maintained throughout, as
long as the fluid is confined. In other words, the
pressure in the fluid is the same everywhere within
the container.
FORCE MULTIPLICATION
Using the 10 PSI example used in the illustration
(Fig. 192), a force of 1000 lbs. can be moved with a
force of only 100 lbs. The secret of force multiplica-
tion in hydraulic systems is the total fluid contact
area employed. The illustration, (Fig. 192), shows an
area that is ten times larger than the original area.
The pressure created with the smaller 100 lb. input
is 10 PSI. The concept ªpressure is the same every-
whereº means that the pressure underneath the
larger piston is also 10 PSI. Pressure is equal to the
force applied divided by the contact area. Therefore,
by means of simple algebra, the output force may be
found. This concept is extremely important, as it is
also used in the design and operation of all shift
valves and limiting valves in the valve body, as well
as the pistons, of the transmission, which activate
the clutches and bands. It is nothing more than
using a difference of area to create a difference in
pressure to move an object.
PISTON TRAVEL
The relationship between hydraulic lever and a
mechanical lever is the same. With a mechanical
lever it's a weight-to-distance output rather than a
pressure-to-area output. Using the same forces and
areas as in the previous example, the smaller piston
(Fig. 193) has to move ten times the distance
required to move the larger piston one inch. There-fore, for every inch the larger piston moves, the
smaller piston moves ten inches. This principle is
true in other instances also. A common garage floor
jack is a good example. To raise a car weighing 2000
lbs., an effort of only 100 lbs. may be required. For
every inch the car moves upward, the input piston at
the jack handle must move 20 inches downward.
Fig. 191 Pressure on a Confined Fluid
Fig. 192 Force Multiplication
Fig. 193 Piston Travel
BR/BEAUTOMATIC TRANSMISSION - 42RE 21 - 239
PISTONS (Continued)