The RT-111 O and RT-12510 transmissions are designed for
heavy-duty on-highway equipment. The twin countershaft
design, which splits torque equally between the two shafts,
provides a high torque capacity to weight ratio . Because of
torque splitting, each gear set carries only half the load,
greatly reducing the face width of each gear.
Another unique design feature is the floating gear principle.
The mainshaft gears when not engaged “float” between the
countershaft gears, eliminating the need for gear sleeves and
bushings. All gears are in constant mesh and have spur type
teeth.
The RT-111 O and RT-12510 transmissions have ten forward speeds and two reverse, consisting of a five-speed
front section and a two-speed auxiliary or range section,
both contained in one case. First through fifth speeds are
obtained by using the five gear ratios in the front section
through the low speed gear of the range section. Sixth
through tenth speeds are obtained by using the five gear
ratios in the front section through the high speed (direct
drive) range gear. As in other Roadranger transmissions, the
ratios are progressively spaced.
The RT-125 15 transmissions have 15 forward speeds and
three consisting of a five-speed front section, which
is identical to the RT-1 110 and RT-1251O front section,
and a three-speed auxiliary or range section. Both sections
are contained in one case, the rear plate being extended to
accommodate the extra set of gears. The 15 speeds are
obtained by using the five speeds of the front section
through direct drive (high range), through the low speed
range gear, and through the hole-gear of the auxiliary sec-
tion. The hole-gear in the RT-12515 transmissions is
engaged by air when selected by the driver.
Openings
Right Side: SAE standard 6 bolt regular duty type, short length.
Bottom: SAE standard 8-bolt heavy-duty type.
PTO Gear Relative Speed to Input R.P. M.
Right
Side: 45-tooth 6/8 pitch gear turning at .700 engine
speed on RT-1 110 and RTF-1 110 models; .888 engine
speed on RTO-1 110 and RTOF-1 110 models.
Bottom: 47-tooth 6/8 pitch gear turning at .700 engine
speed on 110 and RTF-1 110 models, .888 engine
speed on RTO-1 110 and RTOF-1 110 models.
Weight
SAE No. 1 aluminum clutch housing with standard controls,
less clutch release parts – 620 lbs.
Oil Capacity
Approximately 25 pints, depending on inclination of engine
and transmission. Fill to level of case filler opening.
Range
Low
Range
GEAR RATIOS
RT-111O and RTF-111O
RATIO % STEP
10th
Range Shift
1.00
1.27 ‘
9th
1.65
8th
7th
2.11
6th
2.74
3.55
5th
4th
4.50
3rd
5.83
2nd
7.49
1 St
9.71
High
Reverse 2.74
Low
Reverse 9.71
2727
3030
28
3030
30
27
3030
28
30
RTO-1 110 and RTOF-1 110
SPEED RATIO % STEP
10th
9th
8th
7th
6th
Range Shift
5th
4th
3rd
2nd
1 St
High
Reverse 2.16
Low
Reverse 7.65
.79
1.00
1.30
28
1.66
2.16
29
2.79
27
3.55
4.59
28
5.90
30
7.65
I
I
Specifications - RT-I 2510 Series
Speeds
Nominal Torque Capacity 1250 lb.-ft.
Power Take-Off
PTO Gear Relative Speed to Input R.P.M.
Weight
Clutch Housing Size
Oil Capacity
10 progressive forward speeds, 2 reverse.
Openings
Right Side: SAE standard 6-bolt regular duty type, short length.
Bottom: SAE standard 8-bolt heavy-duty type.
Right Side: 45-tooth 6/8 pitch gear turning at .700 engine
speed on RT-1 2510 and RTF-12510 models, .888 engine
speed on RTO-1 2510 and RTOF-1251O models.
Bottom: 47-tooth 6/8 pitch gear turning at .700 engine
speed on RT-1251O and RTF-1 2510 models, .888 engine
speed on RTO-1 2510 and RTOF-12510 models.
SAE No. 1 clutch housing with standard controls, less clutch
release parts – 698 lbs.
SAE No. 1 deep only, 6-5/8”, for push or pull type clutches.
Approximately 25 pints, depending on inclination of engine
and transmission. Fill to level of case filler opening.
High
Range
Low
Range
GEAR RATIOS
RT-1251O and RTF-1251O
;PEED RATIO % STEP
9th
8th
7th
6th
5th
4th
3rd
2nd
1 St
Shift
1.00
1.27
1.65
2.11
2.74
3.55
4.50
5.83
7.49
9.71
2.74
9.71
27
29
28
30
29
27
29
28
30
10th
High
Reverse
Low
Reverse
RTO-125 10 and RTOF-12510
SPEED RATIO % STEP
10th
9th
8th
7th
6th
Range Shift
5th
4th
3rd
2nd
1 St
High
Reverse
Low
Reverse
.79
1.00
1.30
1.66
2.16
2.79
3.55
4.59
5.90
7.65
2.16
7.65
27
30
28
30
29
27
30
28
30
Specifications -
RT-1 2515 Series
Speeds
15 forward speeds, 3 reverse. Five deep reduction ratios,
plus evenly spaced ratios for a selective 11 or 12 progressive
ratios.
Nominal Torque Capacity
1250 lb.-ft.
Power Take-Off
Openings
Right Side: SAE standard 6-bolt regular duty type, short length.
Bottom: SAE standard 8-bolt heavy-duty type.
PTO Gear Relative Speed to Input R.P. M.
RT-12515 and RTF-12515
Right Side: 45-tooth 6/8 pitch gear turning .700 engine speed.
The use of mild EP gear oil or multi-purpose gear oil is not recommended, but if
these gear oils are used, be sure to adhere to
the following limitations:
Do not use mild EP gear oil or multi-purpose gear oil when operating temperatures are
above 230°F (110
o
C). Many of these gear oils,
particularly 85W140, break down above 230°F
and coat seals, bearings and gears with deposits that may cause premature failures. If
these deposits are observed (especially a coating on seal areas causing oil leakage), change
to Eaton Roadranger CD50 transmission fluid,
heavy duty engine oil or mineral gear oil to
assure maximum component life and to maintain your warranty with Eaton. (Also see
“Operating Temperatures”.)
Additives and friction modifiers are not recom-
mended for use in Eaton Fuller transmissions.
Proper Oil Level
Make sure oil is level with filler opening. Because you can reach oil with your finger does
not mean oil is at proper level. One inch of oil
level is about one gallon of oil.
Draining Oil
Drain transmission while oil is warm. To drain
oil remove the drain plug at bottom of case.
Clean the drain plug before re-installing.
Refilling
Clean case around filler plug and remove plug
from side of case. Fill transmission to the
level of the filler opening. If transmission has
two filler openings, fill to level of both openings.
The exact amount of oil will depend on the
transmission inclination and model. Do not
over fill—this will cause oil to be forced out
of the transmission.
When adding oil, types and brands of oil
should not be mixed because of possible incompatibility.
4
LUBRICATION
Operating Temperatures
—With Eaton
®
Roadranger
®
CD50 Transmission Fluid
Heavy Duty Engine Oil
and Mineral Oil
The transmission should not be operated con-
sistently at temperatures above 250
However, intermittent operating temperatures
o
to 300
F (149oC) will not harm the transmission. Operating temperatures above 250
increase the lubricant’s rate of oxidation and
shorten its effective life. When the average
operating temperature is above 250
transmission may require more frequent oil
changes or external cooling.
The following conditions in any combina-
tion can cause operating temperatures of over
o
F: (1) operating consistently at slow
250
speeds, (2) high ambient temperatures, (3) restricted air flow around transmission, (4) exhaust system too close to transmission, (5)
high horsepower, overdrive operation.
External oil coolers are available to reduce
operating temperatures when the above conditions are encountered.
o
F (120oC).
o
F
o
F, the
Proper Lubrication Levels
as Related to Transmission
Installation Angles
If the transmission operating angle is more
than 12 degrees, improper lubrication can occur. The operating angle is the transmission
mounting angle in the chassis plus the percent of upgrade (expressed in degrees).
The chart below illustrates the safe percent
of upgrade on which the transmission can be
used with various chassis mounting angles.
For example: if you have a 4 degree transmission mounting angle, then 8 degrees (or 14
percent of grade) is equal to the limit of 12
degrees. If you have a O degree mounting
angle, the transmission can be operated on a
12 degree (21 percent) grade.
Anytime the transmission operating angle of
12 degrees is exceeded for an extended
period of time the transmission should be
equipped with an oil pump or cooler kit to
insure proper lubrication.
Note on the chart the effect low oil levels
can have on safe operating angles. Allowing
the oil level to fall 1/2” below the filler plug
hole reduces the degree of grade by approximately 3 degrees (5.5 percent).
Proper Lubrication Levels are Essential!
Transmission Oil Coolers are:
Recommended
— With engines of 350 H.P. and above
with overdrive transmissions
Required
— With engines 399 H.P. and above with
overdrive transmissions and GCW’S
over 90,000 lbs.
— With engines 399 H.P. and above and
1400 Lbs.-Ft. or greater torque
— With engines 450 H.P. and above
With EP or Multipurpose Gear Oil
—
Mild EP gear oil and multipurpose gear oil are
not recommended when lubricant operating
temperatures are above 230°F (110). In addition, transmission oil coolers are not recommended with these gear oils since the oil
cooler materials may be attacked by these
gear oils. The lower temperature limit and oil
cooler restriction with these gear oils gener-
ally limit their success to milder applications.
Transmission Mounting Angle
Dotted line showing “2 Quarts Low” is for
reference only. Not recommended.
5
Operation
In the following instructions, it is assumed that the driver is familiar with motor trucks and tractors, and that he can
coordinate the necessary movements of the shift lever and clutch pedal to make progressive and selective gear engagements in
either direction, up or down.
RT-I 110 and RT-12510 Operation
The RT-1 110 and RT-12510 have ten selective ratios, evenly and progressively spaced. Do not shift these transmissions as you would a conventional model with an auxiliary
or two-speed axle, because there is no split-shifting.
All shifts are made with one lever. The range control button
is used one time only during an upshift sequence, and one
time only during a downshift sequence.
Ten speeds obtained with one gear shift lever and range control button.
Since the transmissions consist of a five-speed front section
and a two-speed range section, the ten forward speeds are
obtained by using a five-speed shifting pattern twice – the
first time with the transmission in low range, and the
second time with the transmission in high range.
Shift pattern for the RT-1110 and R T-1251 O model transmissions.
Shift pattern for the R TO-1I10andRTO-12510 model transmissions.
10
Upshifting
To get to high range
pull button
while in 5th speed,
then move lever
to 6th speed.
UP
Downshifting
To get to low range
push button DOWN
6th speed,
then move
lever to 5th speed.
speed.
10
9
8
RANGE
7
6
Upshifting
1. Move the gearshift lever to the neutral position.
2. Start the engine.
3. Wait for air system to reach normal line pressure.
4. Now look at the Range Control Button. If it is up push
it to the down position. (With the downward movement
of the button, the transmission will shift into low range.)
If the button
was down when the truck was last used,
the transmission is already in low range.
5. Now start the vehicle and shift progressively through 1st,
2nd, 3rd and 4th to 5th.
6. When in 5th and
ready for the next upward shift, PULL
the Range Control Button UP and move the lever to 6th
speed. As the lever
passes through the neutral position,
the transmission will automatically shift from low range
to high range.
7. With the transmission in high range, you may now shift
progressively through 7th, 8th and 9th to 10th.
Downshifting
1. When shifting down, move the lever from 10th through
each successive lower speed to 6th.
2. When in 6th, and ready for the next downward shift,
PUSH
the Range Control Button DOWN and move the
lever to 5th speed. As the lever
tral position,
the transmission will automatically shift
passes through the neu-
from high range to low range.
3. With the transmission in low range, shift downward
through each of the four remaining steps.
Driving tip: always start vehicle moving in first speed gear.
11
General Instructions
Precautions
The shift through neutral is important only on the first
shift made after the control button is moved. Subsequent
shifts through neutral will not activate the automatic range
shift until the control button is moved once more.
When necessary to slow or
,.
.
stop the vehicle, shift
down through the individual short steps, allowing
the compression of the engine to slow the vehicle.
The life of chassis and
trailer brakes can thus be
prolonged.
When slowing the vehicle, it is also permissible to coast in
high range with the clutch disengaged. The shift to low
range, however, should not be made until it is necessary to
accelerate the vehicle once more.
Shifts will be fast and short as the gear shift lever stroke is
2% inches between positions. Conical engagement teeth are
standard on these transmissions,
gear clashing. Gear ratios average
thus helping to eliminate
26 per cent between ratio
steps.
To protect the transmission from abuse, the following precautions should be observed when shifting the vehicle:
1. Do not attempt to shift
from high range to low
range at high vehicle
speeds.
This downward
range shift should be made
only at a road speed equal
to that provided by fifth
or a
lower gear at governed
engine speed.
Do not attempt to make any range shifts either up or
2.
down when the vehicle is moving in reverse. Stay in the
range originally selected.
A mylar shift diagram is furnished with each transmission
should be installed on the vehicle dashboard. If it has been misplaced,
Service
Kalamazoo, Michigan.
new m
shift diagrams can be purchased from the
t, Transmission Division, Eaton Corporation,
Skip Shifting
After becoming proficient in shifting this transmission, the
operator may wish to skip some of the gear ratios to offset
a particular Operating condition.
Skip shifting can be
done when upshifting providing the range control
button is pulled up to the
high range position before
making any shift which
passes fifth speed.
Skip shifting is also possible during downshifting
providing the range control button is pushed
down to the low range
position before making any shift which passes sixth speed.
12
RT-12515 and RTO-12515 Operation
The RT-125 15 transmission, like the RT-125 10, has a fivespeed front section and a two-speed auxiliary or range section which enables the driver to select 10 forward
speeds, evenly and progressively spaced. However, the
RT-125 15 models have an additional five speeds obtained
through a deep reduction gear (hole-gear).
The 10 ratios in high and low range are obtained with one
lever and a range control button. The five speeds in deep
reduction are obtained with the same gearshift lever and a
Deep Reduction Valve which controls the “IN” or “OUT”
position of the reduction gear.
The five ratios in deep reduction are evenly and progressively spaced. These five ratios, however, overlap the low range
ratios and are not progressively spaced in relation to the
low range ratios.
The deep reduction gear should be used only when
SHIFTING DIAGRAM OF THE RT-12515
Fifteen speeds obtained with one gear lever, a
Range Control Button and a Deep Reduction Valve.
(Ratios shown with each gear shift lever position.)
operating under adverse conditions and only when the
transmission is in LOW RANGE with the control valve button down. Never move the Deep Reduction Valve to “IN”
when in high range. When the valve is moved to “IN” the
reduction ratios will be engaged regardless of the position
of the Range Control Button.
The RTO-12515 is operated in the same manner as the
RT-125 15 except for the reversal of the 4th and 5th gearshift lever positions.
Upshift Through Low and High Range
Shift upward through the 10 speeds of low and high range
in the same manner as upshifting the RT-12510 or RTO12510 model transmissions. MAKE SURE THE DEEP REDUCTION VALVE IS IN THE “OUT” POSITION AT ALL
TIMES during the low and high range shifts.
SHIFTING DIAGRAM OF THE RTO-12515
Fifteen speeds obtained with one gear shift lever, a
Range Control Button and a Deep Reduction Valve.
(Ratios shown with each gear shift lever position.)
One through 10 speeds . . .
and Deep Reduction gear disengaged.
. . .
Five additional ratios . . .
gaged.
with Range Control Button
with Deep Reduction gear en-
One through 10 speeds . . .
and Deep Reduction gear disengaged.
. . .
Five additional ratios
engaged.
13
. . .
with Range Control Button
with Deep Reduction gear
SUGGESTED SHIFT PATTERN FOR THE RT-12515 THROUGH REDUCTION AND LOW AND HIGH RANGE
(Ratios shown next to each gear shift lever position)
Shift 1 through 5 with range
Move deep
Pull range control button up while in 5th of low range . . . and shift
reduction valve to “OUT”
control button down and deep reduction valve to “IN”
while in 5th reduction . . .
and shift through 4th &
6th through 10th
5th of low range
Upshift Through Deep Reduction,
Low and High Range
There are several patterns of upshifting depending upon 2.
conditions of road and load. Check gear ratios to determine
the best ratio split for your particular condition. The following instructions are recommended for average condi- 3.
tions:
1. With the gearshift lever in neutral, the engine started and 4.
air system pressure normal, PUSH THE RANGE CONTROL BUTTON TO THE DOWN POSITION.
14
Move the Deep Reduction Valve
to the “IN” position to
engage the deep reduction gear.
Start the vehicle and shift progressively from 1st through
5th of the shift pattern.
When in 5th speed position and ready for the next upshift, move the Deep Reduction Valve to the “OUT”
position and shift to the 4th speed position, thus shifting
out of the reduction ratios to low range ratios. Torque
will keep the reduction gear engaged until the shift out
of fifth position is made. Remember, although
the shift
lever is moved from 5th to 4th, this is an upshift and
accelerator must be moved accordingly. There will be no
automatic range shift as the transmission already is in
low range.
5. Shift through the 4th and 5th speed positions of low
range.
6. When ready for the next upshift, pull the Range Control
Button up while in the 5th speed position of low range
and shift the lever to the first speed position of the shift
pattern. As the lever passes through neutral, the transmission will automatically shift from low to high range.
7. Shift progressively upward from 6th through 10th in
high range.
NOTE: The above is for the RT-12515. RTO12515 shift from reduction to low range would differ,
according to the ratios desired.
Important Procedures
1. When making the shift from a reduction ratio to a low
range ratio, move the Deep Reduction Valve from “IN”
to “OUT” IMMEDIATELY BEFORE making the shift.
This is not a pre-select valve and only torque will hold
the reduction gear after the lever is moved to “OUT”;
the shift cylinder will make the shift by air as soon as
torque is released.
2. Never move the Deep Reduction Valve lever with the
transmission in high range (range control button up) as
the reduction gear bypasses both the low and high range
sections, regardless of the position of the range control
button.
3. When downshifting it should not be necessary to shift
into deep reduction ratios. The reduction in low range
should be sufficient in most operating conditions.
All instructions pertaining to the Range Control Button, skip shifting and general precautions of the ten-speed shift pattern of
the RT-1 110 and RT-1251O apply as well to the RT-12515.
15
Air Systems
Range Shift Air System – All Models
This system consists of an air filter, regulator, air valve,
control valve, shift cylinder, fittings and connecting lines.
See Illustration A.
Constant regulated air is supplied to the bottom port of the
air valve and to the “IN” port of the control valve. With the
control button down, air passes through the control valve
and to the end port of the air valve. This permits air from
the constant supply to flow through the low range port in
bottom, side cap of air valve and to the shift cylinder air
port. Air on this port moves the shift piston and bar to the
rear to engage the low range gear.
With the control button up the control valve is closed and
air is removed from end port of air valve. This permits air
from the constant supply to flow through the high range
port in rear, side cap of air valve and to the shift cylinder
cover air port. Air on this port moves the shift piston and
bar forward to engage the high range gear.
When the control button is moved from one position to
another, air from the previously charged line exhausts
through the breather in air valve.
On some transmissions the air valve may be installed in a
180° position from that shown in Illustration A. The porting on these models, however, remains the same. The bottom port in the side cap is always the low range port.
16
Hole-Gear Air System – RT-12515 Series
This system uses the air filter and regulator of the range
shift air system, plus a Deep Reduction Valve, mounted in
the vehicle’s cab, and a hole- gearshift cylinder. See Illustration B.
Constant regulated air is supplied to the end port of the
deep reduction valve and to the air port in the lower, right
side of the hole -gearshift cylinder cover.
The deep reduction valve lever has two positions, “IN” and
“OUT”. With the lever moved to the “IN” position the
valve is off. Thus, constant air channeled through the shift
cylinder and cover to the front of the shift piston moves
the piston and shift bar to the rear to engage the hole-gear.
As the hole-gear is engaged the range mainshaft is disengaged from the output shaft, removing the low and high
range sections from the power flow.
With the deep reduction valve lever moved to the “OUT”
position air flows out the side port of the valve and to the
air port near the center of the hole -gearshift cylinder cover.
This air, pushing against a larger piston area than the constant air supply, moves the shift piston and bar forward to
disengage the hole-gear. As the hole-gear is disengaged, the
range mainshaft is engaged to the output shaft, permitting
use of the low and high range sections.
B. Hook-up diagram and troubleshooting checkpoints for
the hole-gear air system.
17
Air Valve Operation
With the range control button up the control valve shuts off
the air supply to the end cap. Thus, the constant air
ing at the constant supply port forces the piston to the rear.
The constant air also flows through a channel in the center
of the piston and to an external port which is aligned with
the high range port of the air valve.
C. Exploded view of value. The alignment sleeve not part of assembly, but must be housing for
proper
operation.
With the control button down the control valve opens and
supplies air to the end cap. Since the piston area is larger on
this end of the piston, it is forced in the opposite direction.
The external air port in the piston is now aligned with the
low range port of the air valve.
The four O-rings are indicated by circled numbers. If any of these are defective, there will be a constant air leak out of the
exhaust on the air valve. In normal operation, exhaust will occur only for an instant as the range shift is made. The following
chart is to be used as a guide to determine defective O-rings.
Defective
O-Rings
1
2or3
4
Constant leak through exhaust in low range only.
Constant leak through exhaust in both ranges.
Constant leak through exhaust in high range; steady but low volume
RESULT
leak through exhaust in low range.
To Disassemble Air Valve
Turn out the two capscrews and remove the side cap 4.
1.
from valve body.
Remove the valve insert from piston and remove O ring 5.
2.
from the valve insert.
Remove the spring from piston.
3.
Turn end cap from valve body and withdraw piston from
bore.
Remove the two O-rings from piston.
Remove the nylon plug from piston and remove O-ring
6.
from plug.
18
Air Valve Pre-Selection
An actuating pin protruding from the shifting bar housing
prevents the actuating piston in the air valve from moving
while the gearshift lever is in a gear position and releases the
SLEEVE
D, Cross-section actuating pin and plunger assembly.
piston when the lever is moved to or through neutral. See
detailed installation of air valve for installation precaution
concerning the actuating pin.
Air Regulator
The air regulator is not serviceable. If defective replace the
air regulator unit. Reading at output of air regulator should
be 57.5 to 62.5 psi.
Air Filter & Regulator Assembly
19
E. Exploded of control value. The
air to cap of air ualoe.
“IN’’port
constant
If the O-rings or parts in the control valve are defective
there will be a constant air leak out the exhaust located on
bottom of control valve.
A
defective insert valve O-ring will result in a constant leak
through exhaust in both ranges and valve will not make
range shifts.
A defective housing O-ring will result in a constant, low
volume leak through exhaust in low range only.
If the slide is assembled backwards, there will be a constant
leak through exhaust in high range. When installing slide in
control valve make sure that slot in slide faces the outlet
part.
To Disassemble the Control Valve
1. Remove the four screws to separate front and rear housings.
supply. The “OUTLET” port connected by O. L).
2.
Remove the slide and the two position balls and springs.
Remove the flat metal seal from outlet side and remove
3.
the O-ring from body.
Remove the valve insert from front housing and re-
4.
move the O-ring from valve insert.
Remove the wave washer installed under valve insert.
5.
Remove
6.
Punch out roll pin and remove control button from
7.
slide.
Qty.
2
1
1
1
1
the two felt wipers from valve housings.
Air Valve O-Ring sizes, Ill. C
Location
Valve Insert and Plug
Piston
Piston
Control Valve O-Ring sizes, Ill. E
Valve Insert.301
Housing.375
IDWidth
.208
.549
.364
.070
.103
.070
.070
.062
20
Trouble Shooting
Range Shift Air System All Models
The following checks are to be made with normal vehicle air pressure but with the engine off. Refer to Illustration A for
check points.
Incorrect Hook-Up
1.
With normal vehicle air pressure and gearshift lever in
the neutral position, move the control button up and
down, from one range to another.
If lines are crossed between the control valve and the
a.
air valve on transmission, there will be a steady flow
of air from the top exhaust in control valve if button
is held in the up position.
If lines are crossed between the air valve on transmis-
b
sion and the air or shift cylinder, the transmission
gearing will not correspond with the button position.
Low range, down position of button, will result in
high range gear engagement in the transmission and
vice versa.
Air Leaks
2.
With normal vehicle air pressure and gearshift lever in
the neutral position, coat all air lines and fittings with
soapy water and check for leaks, moving control button
to
both positions.
If there is a steady leak out exhaust of control valve,
a.
there are defective parts or O-rings in the control
valve.
If there is a steady leak out breather on air valve;
b.
there is a defective O-ring in the air valve; or there is a
leak past O-rings on the shift cylinder piston (see Ill.
F, Check Point E).
If transmission fails to shift into low range or is slow
c.
to make the shift and the transmission case is pressurized, see Ill. F, Check Point E.
Tighten all loose connections and replace defective
d.
parts or O-rings.
3.
Air Regulator, Check Point A
With normal line pressure and gearshift lever in neutral,
check exhaust port on side of air regulator. There should
be no leak from this port.
If there is a steady leak from exhaust port, this indicates
a defective air regulator and should be replaced.
Cut off the vehicle air pressure and install air gauge in
line at output port of air regulator. Bring vehicle air
pressure to normal. Regulated pressure should be 57.5 to
62.5 psi.
If correct pressure readings are not obtained, replace
regulator.
4.
Control Valve, Check Point B
With the gearshift lever in neutral, pull the control but-
ton up to high range and disconnect the 1/8" black
nylon air line at air valve.
a,
When control button is pushed down a steady blast of
air should flow from the disconnected line. Air will
shut off when button is pulled up. This indicates that
control valve is operating correctly. Reconnect air
line. If control valve does not operate correctly,
check for leaks, restrictions and defective O-rings.
5.
High Range, Check Point C
With the gearshift lever in neutral, push the control button down and disconnect the high range air line from the
shift cylinder cover.
a.
Pull the control button up. There should be a steady
flow of air from the high range air line. Push button
down to shut off air.
b.
Make sure vehicle engine is off and move the gearshift
lever to a gear position. Pull the button up; there
should be no air at high range line. Move the gearshift
lever to neutral; there should now be a steady flow of
air from the high range line. Push button down to
shut off air and reconnect line.
c.
If air system operated incorrectly, this indicates that
air valve is defective or that actuating parts in shifting
bar housing are jammed or defective.
21
6. Low Range, Check Point D
With the gearshift lever in neutral, pull the control button up and disconnect the low range air line at shift
cylinder.
a. Repeat procedure under Check Point C, reversing the
position of the control button in order to check the
low range operation.
7. Range Shift Cylinder – Check Point E
If any of the seals in the range shift cylinder are defective the range shift will be affected. The degree of lost
air, of course, will govern the degree of failure, from
slow shift to complete failure to shift.
Refer to Illustration F for location of seals. Make sure
cylinder bore is clean to prevent damage to piston seal.
Use only a very light amount of shellac or Permatex on
cover gasket to prevent clogging cylinder. Tighten cover
capscrews securely.
22
Hole-Gear Air System
RT-12515 and RTO-12515 Transmissions
The following checks are to be made with normal vehicle air pressure but with the engine off. It is assumed air lines have been
checked for leaks and the air regulator has been checked and the correct reading obtained. Refer to Illustrat
on B for check
points.
1.
Air Input – Check Point F
With gearshift lever in neutral and normal vehicle air
pressure, loosen the connection at input (end port) of
the deep reduction valve until it can be determined that
there is a constant flow of air at this point. Reconnect
line.
If there is no air at this point, there is a restriction in the
line between the deep reduction valve and air valve. Also
Refer to Illustration
Leak at seal A . . . .
Leak at seal B....
G, for location of seals
Failure to engage hole-gear; pressurizing of transmission; hole-gear
can be disengaged.
Failure to engage hole-gear; leak
from deep reduction valve exhaust
port when valve is “IN”.
check to make sure this line is connected to constant
supply.
Deep Reduction Valve – Check Point G
2.
G. Cutaway. Deep Reduction Shift Cylinder. (R T-12515 models)
With the deep reduction valve lever to “IN”, remove the
line from the deep reduction valve at the port in hole-
gearshift cylinder; there should be no air at this point.
Move the deep reduction valve lever to “OUT”. There
should now be a constant air flow from line. Move lever
to “IN” to shut off air. If the above conditions do not
exist, deep reduction valve is faulty or there is a restric-
tion in air line.
Hole-Gearshift Cylinder – Check Point H
3.
If any of the seals in the hole-gearshift cylinder are defective the hole-gearshift will be affected. The degree of
lost air, of course, will govern the degree of failure, from
slow shift to complete failure to shift.
23
Preventive Maintenance Check Chart
CHECKS WITHOUT PARTIAL
DISASSEMBLY OF
CHASSIS OR CAB
1.
Air System and Connections
a. Check for leaks, worn air lines, loose connections and
capscrews. See Air Systems.
2.
Clutch Housing Mounting
a. Check all capscrews in bolt circle of clutch housing
for looseness. Tighten to recommended torque.
3.
Clutch Release Bearing
a. Remove hand hole cover and check radial and axial
clearance in release bearing.
b. Check relative position of thrust surface of release
bearing with thrust sleeve on push type clutches.
4.
Clutch Pedal Shaft and Bores
a. Pry upward on shafts to check wear.
b. If excessive movement is found, remove clutch release
mechanism and check bushings in bores and wear on
shafts.
8. Gearshift Lever Housing Assembly
Remove air lines at air valve and remove the gearshift
a.
lever housing assembly from transmission.
b.
Check tension spring and washer for set and wear.
c.
Check the gearshift lever pivot pin and pivot pin slot
for wear.
Check bottom end of gearshift lever for wear and
d.
check slot of yokes and blocks in shift bar housing
for wear at contact points with shift lever.
CHECKS WITH DRIVE LINE
DROPPED
9. Universal Joint Companion Flange Nut
a. Check for tightness. Tighten to recommended torque.
CHECKS WITH UNIVERSAL JOINT
COMPANION FLANGE REMOVED
10. Splines on Output Shaft
a. Check for wear from movement and chucking action
of the universal joint companion flange.
5.
Gear Lubricant
a. Change at specified service intervals.
b. Use only gear oils as recommended. See Lubrication
section.
Filler and Drain Plugs
6.
a. Remove filler plug and check level of lubricant at
specified intervals.
Tighten filler and drain plugs
securely.
7.
Gear Shift Lever
a. Check for looseness and free play in housing. If lever
is loose in housing, proceed with Check No. 8.
11. Mainshaft Rear Bearing Cover
a. Check oil seal for wear.
12. Output Shaft
a. Pry upward against output shaft to check radial clear
ante in mainshaft rear bearing.
24
-
. . .
25
Special Procedure For
Clutch (Input) Shaft
In some cases in field repair it may benecessary to replace
only the input shaft due to clutch wear on the splines.
In these instances the input shaft can be removed without
disassembling the transmission other than removing the
shifting bar housing. Removal of the clutch housing is optional. Following is the detailed procedure:
Disassembly
Remove gearshift lever housing and shift bar housing
1.
from transmission.
Remove the front bearing cover.
2.
Engage the mainshaft sliding clutches in two gears and
3.
remove the drive gear bearing nut.
4.
Move the drive gear assembly as far forward as possible
and remove the drive gear bearing.
5.
Remove the washer from input shaft.
From the front, remove the snap ring from ID of drive
6.
gear.
7.
Pull the input shaft forward and from splines of drive
gear.
2.
Install snap ring in ID of drive gear.
Install washer on shaft.
3.
Move the fourth-fifth speed sliding clutch gear forward
4.
to contact end of input shaft
hub of drive gear. Block
between rear of sliding clutch and front of the fourth
speed gear. When installing bearing this will hold input
shaft in position to seat the bearing properly.
Install drive gear bearing on shaft and into case bore,
5.
making sure blocking remains in place.
Remove blocking from mainshaft and install the drive
6.
gear bearing nut, left-hand thread. Use Loctite sealant on
threads of nut and shaft.
Peen nut into milled slots in shaft.
7.
Re-install front bearing cover, shifting bar housing and
8.
gearshift lever housing.
NOTE: 7%e above instructions are for changing the input shaft only. To change the drive gear, complete disassembly of the fron t section must be made.
Reassembly
1. Install new input shaft into splines of drive gear just far
enough to expose snap ring groove in ID of drive gear.
Make sure
the input shaft.
that the bushing is installed in the pocket
26
General Precautions for Disassembly
IMPORTANT: Read this section before starting
the detailed disassembly procedures.
[t is assumed in the detailed disassembly instructions that
the lubricant has been drained
necessary linkage and air lines removed and the transmission has been removed from the chassis. Removal of the
gearshift lever housing assembly is included in the detailed
instructions; however, this assembly must also be removed
from transmission before removing unit from vehicle.
On
RT-12515 and RTO-I2515 models, air lines from the
hole-gear switch in cab must be disconnected at the transmission before removing unit from vehicle.
Follow
each procedure closely in each section, making use
of both the text and pictures.
BEARINGSCarefully wash and relubricate all bear-
1.
ings as removed and protectively wrap until ready for
use. Remove all bearings with pullers designed for this
purpose
punch.
-- do not remove bearings with hammer and
from the transmission, the
2.
SNAP RINGS Remove snap rings with pliers designed
for this purpose. Rings removed in this manner can be
reused.
INPUT SHAFT The clutch
3.
moved on most models without removing the countershaft, mainshaft or drive gear. See page 26.
4.
CLEANLINESS Provide a clean place to work. It is
important that no dirt or foreign material enters the unit
during repairs.
fully cleaned before starting the disassembly. Dirt is
abrasive and can damage highly polished parts such as
bearings, sleeves and bushings.
or input shaft can be re-
The outside of the unit should be care-
5.
WHEN DRIVING Apply force to shafts, housings,
etc., with restraint. Movement of some parts is re-
stricted.
stops solidly. Use soft hammers and bars for all disassembly work.
27
Do not apply force after the part being driven
1. Shifting Controls.
28
Removal of the Deep Reduction Shift Air
A.
1. Remove the 1/4" ID air line between the deep reduction
shift cylinder and the tee fitting forward of the filter /
regulator assembly.
System D
RT-12515 Series
B. Removal of the Range Shift Air System
1. Disconnect the black and white 1/8" OD air line at the
air valve on the side of the transmission.
NOTE: The gear shift lever housing, range control valve
and lines may now be removed as a unit by turning out
the four capscrews at the base of the gear shift lever
housing.
2. Disconnect the black and white 1/8" O D air line at the
range control valve on the shift lever.
29
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