Eaton Transmission Clark 280VHD Service Manual
Service Manual
Fuller Mid Range Transmissions
TRSM0195
October 2007
For parts or service call us
Pro Gear & Transmission, Inc.
1 (877) 776-4600
(407) 872-1901
parts@eprogear.com
906 W. Gore St.
Orlando, FL 32805
Caution - Before towing the vehicle, be sure to lift the rear wheels off the ground or disconnect the driveline to
avoid damage to the transmission during towing.
FOREWARD
This manual has been prepared to provide the customer and the maintenance personnel with information and instructions on the maintenance and repair of the CLARK® Transmission.
Extreme care has been exercised in the design, selection of materials and manufacturing of these units. The slight outlay in personal attention and cost required to provide regular and proper lubrication, inspection at stated intervals, and
such adjustments as may be indicated will be reimbursed many times in low cost operation and trouble free service.
In order to become familiar with the various parts of the transmission, its principle of operation, troubleshooting and
adjustments, it is urged that the service person study the instructions in this manual carefully and use it as a reference
when performing maintenance and repair operations.
Whenever repair or replacement of components parts is required, only Clark-approved parts as listed in the applicable
parts manual should be used. Use of “will-fit” or non-approved parts may endanger proper operation and performance
of the equipment. The Clark Equipment Company does not warrant repair or replacement parts, nor failures resulting
from the use thereof, which are not supplied by or approved by the Clark Equipment Company.
IMPORTANT: Always furnish the Distributor with the transmission serial and model number when ordering parts.
CLARK
A
THE CLARK SYNCHRONIZER
AND HOW IT WORKS FOR YOU
The Clark split-pin synchronizer prevents the clashing of the gears and increase the speed of shifting.
In a conventional transmission which does not have synchronizers the absence of gear clashing is dependent entirely
on the skill of the truck driver. By double-clutching and split second timing of engine speeds with the gear shifting
movement, a driver can synchronize the speeds of the engaging gears and thereby prevent the damage to gears by
clashing when a fast shift. The splint-pin sychronzier performs the same function with or without the “double-clutching”
operating even though the driver does not accurately time his gear shifting movements. It also mechanically prevents
the driver from completing the shift to the point of gear engagement until the engaging gears have reached the same or
synchronous speeds. This is known as the blocking action of the synchronizer and it is this action that makes the operation of shifting a transmission having synchronizers different from one which does not have synchronizers.
Upon shifting gears in these synchronized transmissions the first part of the gear shift lever movement brings the
blockers into contact. The blockers momentarily prevent further movement of the shift lever and the pressure exerted
by the driver to complete the movement, is transferred by the blockers to the synchronizer providing the force necessary to synchronize the gears being engaged. When the engaging gears have reached the same speed, the blockers
automatically disengage, permitting the gear shift lever movement to be completed. Therefore, to properly shift a synchronized transmission a steady and continuous pressure must be applied by the driver to the shift lever until the shift
is completed. Under normal conditions this action is instantaneous.
Sometimes difficulty is experienced in shifting a synchronizer when the vehicle is standing still. This is caused by the
fact that the disengagement of the blockers requires relative rotation and with the vehicle at rest and with the engine
clutch released, there may be at times, no relative rotation of the engaging gears. Under these conditions, the same continuous pressure should be applied to the shift lever and at the same time, the clutch should be engaged slightly. This
will give sufficient rotation to unblock the synchronizer and allow the shift to be completed without difficulty.
B
RECOMMENDED LUBRICANTS FOR CLARK
MANUALLY SHIFTED TRANSMISSIONS
*Mil-L-2105C Extreme Pressure Lubricant (or API classification
GL-5) of the SAE viscosity recommended in the chart at the right
is preferred. All lubricants should be backed by the reputation of
a well-know supplier. It is important to specify EP lubricants of
the MIL-L-2105C type only, or of a API classification GL-5.
*Do not use extreme pressure lubricants other than MIL-L2105C or of a API classification GL-5.
Many EP lubricants contain highly-active chemical compounds
that have been formulated to perform satisfactorily in specific
types of applications. Severe corrosion, residual deposits, and
inadequate lubrication may result from improper application. Use
of EP lubricants other that MIL-L-2105C or of a API classification
GL-5 may result in failure and/or impaired operation.
DRAINING ECONOMY - The object in draining the transmission
oil periodically is to eliminate possible bearing surface abrasion
and attendant wear. Minute particles of metal, the product of normal wear in service, are deposited in and circulate with the transmission oil. The oil changes chemically, due to its repeated
heating and cooling, also the terrific churning it undergoes in the
presence of air. It is desirable to drain out this used oil after the
first 1,000 miles (1609,0 Km) of service (regardless of type of
service). Subsequent drains should be made every 24,000 miles
(38616,0 Km) or six (6) months (whichever comes first) for
highway service, and every 8,000 to 10,000 miles [12872,016090,0 Km] or six (6) months (whichever comes first) “on-off”
highway and “pick-up and delivery” types of service. Do this only when the transmission is thoroughly warm.
FLUSHING - After draining, flushing is desirable. Replace the drain plug and fill the transmission to the proper level with
a light flushing oil. Drive the transmission for a short period at fast idle in such a manner that the gears in the transmission are rotating without load. This washes out the old oil clinging to the interior of the gear case, covers and shifter
rails. BE SURE TO DRAIN OUT ALL of the flushing oil before attempting to refill with new oil. This flushing procedure is
most important after first drain.
REFILL - First, removal all dirt around the filler plug, Then refill with new oil of a grade recommended for the existing
season and prevailing service. Fill to the bottom of the level testing plug positioned on the side of the transmission. DO
NOT OVERFILL, as the excess quantity will serve no useful purpose. If the oil level is too high, it will cause excessive oil
churning and high oil temperature and possible leakage.
INSPECTION - Oil level inspection should be made every 6,000 miles [9654,0 Km] which usually coincides with the
vehicle manufacturers chassis lube procedure. Always clean around filler plug before inspection. Add sufficient oil to
maintain correct level.
C
CLARK
D
280VHD SERIES TRANSMISSION
ITEM DESCRIPTION QTY.
1 Shift Rod Cover Screw Lockwasher.......................................14
2 Shift Rod Cover Screw Lockwasher.......................................14
3 Control Assembly.....................................................................1
4 Control Rod Cover Gasket........................................................1
5 4th & 5th Shift Hub Bearing Race............................................1
6 4th & 5th Shift Hub Bearing ....................................................1
7 5th Speed Synchronizer Cup....................................................1
8 4th & 5th Synchronizer Assembly............................................1
9 4th Speed Synchronizer Cup....................................................1
10 4th & 5th Shift Hub Sleeve......................................................1
11 Mainshaft 4th Gear ..................................................................1
12 Mainshaft 3rd Gear Retainer Ring............................................1
13 Mainshaft 3rd Gear Locating Washer.......................................1
14 Mainshaft 3rd Gear .................................................................1
15 Mainshaft 3rd Gear Synchronizer Cup .....................................1
16 2nd & 3rd Gear Synchronizer Assembly ..................................1
17 3rd Gear Shift Hub Sleeve Retainer Ring .................................1
18 2nd & 3rd Gear Shift Hub Sleeve .............................................1
19 2nd Gear Shift Hub Sleeve Retainer Ring.................................1
20 Mainshaft 2nd Gear..................................................................1
21 Mainshaft 2nd Gear Locating Washer......................................1
22 Mainshaft 2nd Gear Retaining Ring .........................................1
23 Mainshaft ................................................................................1
24 Mainshaft 1st & Reverse Gear .................................................1
25 Mainshaft Rear Bearing Cone...................................................1
26 Countershaft Rear Bearing capscrew .......................................4
27 Countershaft Rear Bearing capscrew Lockwasher ...................4
28 Countershaft Rear Bearing Cap................................................1
29 Countershaft Rear Bearing Cap Gasket ....................................1
30 Countershaft Rear Bearing Retainer Ring ................................1
31 Countershaft Rear Bearing Retainer Ring (Outer) ....................1
32 Countershaft Rear Bearing.......................................................1
33 Countershaft ...........................................................................1
34 Countershaft Gear Key.............................................................2
35 Countershaft 4th Gear..............................................................1
36 Countershaft Drive Gear...........................................................1
37 Countershaft Drive Gear Retainer Ring ....................................1
38 Nameplate................................................................................1
39 Nameplate Screw ....................................................................2
40 Oil Level & Filler Plug...............................................................1
41 Magnetic Drain Plug ................................................................1
42 Mainshaft Flange Nut ...............................................................1
43 Mainshaft Rear Bearing Cap Oil Seal........................................1
44 Mainshaft Rear Bearing capscrew............................................3
45 Mainshaft Rear Bearing capscrew Lockwasher........................3
ITEM DESCRIPTION QTY.
46 Mainshaft Rear Bearing Cap .................................................... 1
47 Mainshaft Rear Bearing Cap Gasket ........................................ 1
48 Speedometer Drive Gear (Optional).........................................1
49 Mainshaft Rear Bearing Cup....................................................1
50 Transmission Case ..................................................................1
51 P.T.O. Cover Plate Gasket.........................................................2
52 P.T.O. Cover Plate....................................................................2
53 P.T.O. Cover Screw & Washer................................................12
54 Mainshaft Rear Bearing capscrew Lockwasher....................... 1
55 Mainshaft Rear Bearing capscrew ...........................................1
56 Speedometer Driven Gear (Optional)....................................... 1
57 Speedometer Tube Nut (Optional)........................................... 1
58 Reverse Idler Shaft Lock Screw...............................................1
59 Reverse Idler Shaft Lock ......................................................... 1
60 Reverse Idler Shaft..................................................................1
61 Reverse Idler Thrust Washer ................................................... 2
62 Reverse Idler Gear Bearing......................................................2
63 Reverse Idler Gear...................................................................1
64 Mainshaft Spigot Bearing Retainer Ring..................................1
65 Mainshaft Spigot Bearing Retainer Ring..................................1
66 Mainshaft Spigot Bearing .....................................................14
67 Main Drive Gear ......................................................................1
68 Main Drive Gear Bearing Cone.................................................1
69 Main Drive Gear Bearing Cup .................................................. 1
70 Main Drive Gear Shim.......................................................... AR
71 Main Drive Gear Bearing Cap Oil Seal......................................1
72 Main Drive Gear Bearing Cap ..................................................1
73 Main Drive Gear Bearing capscrew Lockwasher......................4
74 Main Drive Gear Bearing capscrew..........................................4
75 Clutch Housing Stud Nut......................................................... 4
76 Clutch Housing Stud Nut Lockwasher.....................................4
77 Clutch Housing Stud ............................................................... 4
78 Countershaft Pilot Bearing.......................................................1
79 Clutch Pedal Shaft Grease Fitting ............................................ 2
80 Clutch Housing Inspection Plate Screw................................... 2
81 Clutch Housing Inspection Plate Screw Washer......................2
82 Clutch Housing Inspection Plate.............................................. 1
83 Clutch Pedal Shaft Bushing .....................................................4
84 Clutch Housing........................................................................1
85 Mainshaft Rear Bearing Cap Gasket ........................................ 1
86 Mainshaft Rear Bearing Cap (Optional) ................................... 1
87 Mainshaft Rear Bearing capscrew Washer..............................1
88 Mainshaft Rear Bearing capscrew ...........................................1
89 Output Flange..........................................................................1
90 Mainshaft Rear Bearing Cap Stud Nut..................................... 4
91 Mainshaft Rear Bearing Cap Stud Nut Lockwasher ................. 4
92 Mainshaft Rear Bearing Cap Stud............................................4
E
CLARK
G
280V-SERIES CONTROL PARTS GROUP (Fabricated Rails)
ITEM Description QTY
1 Gear Shift Lever Dust Cover.....................................................1
2 Gear Shift Lever Pivot Pin........................................................2
3 Control Top ..............................................................................1
4 Gear Shift Lever.......................................................................1
5 Gear Shift Lever Support Washer.............................................1
6 Support Spring ........................................................................1
7 Control Top or Remote Control Gasket ....................................1
8 Control Cover...........................................................................1
9 1st & Reverse Rocker Arm ......................................................1
10 1st & Reverse Shift Fork & Rail Assembly...............................1
11 Rear Rail Support ....................................................................1
12 Rear Rail Support Capscrew Lockwasher ................................2
13 Rear Rail Support Capscrew ....................................................4
14 Front Rail Support Capscrew ...................................................4
ITEM Description QTY
16 Front Rail Support................................................................... 1
17 2nd & 3rd, 4th & 5th Shift Fork Bushing.................................4
18 4th & 5th Shift Fork & Rail Ass’y (Includes Item #17)............. 1
19 2nd & 3rd Shift Fork & Rail Ass’y (Includes Item #17) ........... 1
20 Interlock Cross Pin..................................................................1
21 Interlock Tapered Pin Support.................................................2
22 Interlock Tapered Pin...............................................................2
23 1st & Reverse Shift Rail ..........................................................1
24 Mesh Lock Poppet Rails..........................................................4
25 Poppet Springs........................................................................ 4
26 Reverse Latch Plunger ............................................................ 1
27 Plunger Spring ........................................................................1
28 Plunger Spring Retaining Plug ................................................ 1
29 Control Top or Remote Control Capscrew...............................4
15 Front Rail Support Capscrew Lockwasher ...............................4
H
CLARK
I
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