Eaton Transmission Clark 280V Service Manual
Service Manual
Fuller Mid Range Transmissions
TRSM0194
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 dis-
connect 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.
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.
A
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-L2105C 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 [12872,0-16090,0 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.
B
CLARK
C
280V-Series Transmission
Item Description QTY
1 Shift Rod Cover Screw...........................................................14
2 Shift Rod Cover Screw Lockwasher.......................................14
3 Control Cover (Stamped version).............................................1
4 Control Cover Gasket...............................................................1
5 Mainshaft 5th Speed Synchronizer Cup ...................................1
6 Mainshaft 4th & 5th Synchronizer Assembly...........................1
7 Mainshaft 4th Speed Synchronizer Cup ...................................1
8 Mainshaft 4th & 5th Shift Hub Sleeve Retainer Ring................1
9 Mainshaft 4th & 5th Shift Hub Sleeve......................................1
10 Mainshaft 4th Speed Gear........................................................1
11 Mainshaft 3rd Gear Retainer Ring............................................1
12 Mainshaft 3rd Gear Locating Washer.......................................1
13 Mainshaft 3rd Speed Gear .......................................................1
14 Mainshaft 3rd Speed Synchronizer Cup...................................1
15 Mainshaft 2nd & 3rd Synchronizer Assembly..........................1
16 Mainshaft 2nd & 3rd Shift Hub Sleeve Retainer Ring ..............1
17 Mainshaft 2nd & 3rd Shift Hub Sleeve.....................................1
18 Mainshaft 2nd & 3rd Shift Hub Sleeve Retainer Ring ..............1
19 Mainshaft 2nd Speed Gear.......................................................1
20 Mainshaft 2nd Speed Gear Locating Washer ...........................1
21 Mainshaft 2nd Speed Gear Retainer Ring ................................1
22 Mainshaft ................................................................................1
23 Mainshaft 1st & Reverse Gear .................................................1
24 Countershaft Rear Bearing capscrew .......................................4
25 Countershaft Rear Bearing Cap Lockwasher ............................4
26 Countershaft Rear Bearing Cap ...............................................1
27 Countershaft Rear Bearing Cap Gasket....................................1
28 Countershaft Rear Bearing Cap Retainer Ring .........................1
29 Countershaft Rear Bearing ......................................................1
30 Countershaft Rear Bearing Oil Slinger......................................1
31 Countershaft............................................................................1
32 Countershaft Gear Key.............................................................1
33 Countershaft 4th Speed Gear ...................................................2
34 Countershaft Drive Gear...........................................................1
35 Countershaft Drive Gear Retainer Ring ....................................1
36 Filler Plug.................................................................................1
37 Magnetic Drain Plug ................................................................1
38 Flange Nut................................................................................1
39 Flange to Drum Bolt Nut ..........................................................4
40 Flange to Drum Bolt Lockwasher .............................................4
41 Companion Flange...................................................................1
42 Brake Assembly .......................................................................1
Item Description QTY
43 Brake Drum to Flange Bolt....................................................... 4
44 Mainshaft Rear Oil Seal...........................................................1
45 Mainshaft Rear Bearing capscrew ...........................................3
46 Mainshaft Rear Bearing capscrew Lockwasher....................... 3
47 Mainshaft Rear Bearing Cap .................................................... 1
48 Mainshaft Rear Bearing Cap Gasket ........................................ 2
49 Speedometer Drive Gear ......................................................... 1
50 Mainshaft Rear Bearing ........................................................... 1
51 Transmission Case .................................................................. 1
52 P.T.O. Cover Plate Gasket.........................................................2
53 P.T.O. Cover Plate....................................................................2
54 P.T.O. Cover Plate Screw .......................................................12
55 Mainshaft Rear Bearing capscrew Lockwasher....................... 1
56 Mainshaft Rear Bearing capscrew ...........................................1
57 Speedometer Driven Gear ....................................................... 1
58 Speedometer Tube Nut............................................................1
59 Reverse Idler Shaft Lock Screw...............................................1
60 Reverse Idler Shaft Lock ......................................................... 1
61 Reverse Idler Shaft..................................................................1
62 Reverse Idler Thrust Washer ................................................... 2
63 Reverse Idler Bearing.............................................................. 2
64 Reverse Idler Gear...................................................................1
65 Mainshaft Spigot Bearing ........................................................ 1
66 Main Drive Gear.......................................................................1
67 Main Drive Gear Bearing Oil Slinger ........................................1
68 Main Drive Gear Bearing ......................................................... 1
69 Main Drive Gear Bearing Retainer Ring...................................1
70 Main Drive Gear Bearing Cap Oil Seal......................................1
71 Main Drive Gear Bearing Cap Gasket....................................... 1
72 Main Drive Gear Bearing Cap...................................................1
73 Main Drive Gear Bearing capscrew..........................................4
74 Clutch Housing Stud Nut......................................................... 4
75 Clutch Housing Stud Nut Lockwasher.....................................4
76 Clutch Housing Stud ............................................................... 4
77 Countershaft Pilot Bearing.......................................................1
78 Pedal Shaft Grease Fitting .......................................................2
79 Clutch Housing Inspection Plate Bolt ...................................... 2
80 Clutch Housing Inspection Plate Lockwasher.......................... 2
81 Clutch Housing Inspection Plate.............................................. 1
82 Clutch Pedal Shaft Bushing .....................................................4
83 Clutch Housing........................................................................1
D
CLARK
E
280V-SERIES CONTROL PARTS GROUP (Stamped Cover)
ITEM Description QTY
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 Gasket...............................................1
8 Shift Rod Cover....................................................1
9 Shift Rod Cover Gasket........................................1
10 Shift Rod Support Screw and Lockwasher...........4
11 Shift Rod Support................................................1
12 1st & Reverse Shift Fork Lockscrew....................1
13 1st & Reverse Shift Fork......................................1
14 Shift Fork Lock Pin...............................................1
15 4th & 5th Shift Fork Assembly (Inc. Items 16 & 17)1
16 Shift Fork Bushing ...............................................2
32 Reverse Latch Plunger.........................................1
33 Reverse Latch Plunger Retainer Washer..............1
34 Reverse Latch Plunger Spring.............................1
35 1st & Reverse Rocker..........................................1
36 Reverse Latch Plunger Nut..................................1
37 Reverse Latch Plunger Nut Cotter........................1
38 Backup Switch Hole Plug.....................................1
39 Backup Switch Hole Plug Gasket.........................1
40 Welch Plug ..........................................................1
41 Control Top Screw & Lockwasher ...........................................4
17 Shift Fork Bushing ...............................................2
18 Shift Fork Bushing ...............................................2
19 Shift Fork Bushing ...............................................2
20 Shift Fork Lock Pin...............................................1
21 2nd & 3rd Fork Assembly (Inc. Items 18 & 19) ...1
22 2nd Speed Overshift Spacer.................................1
23 Reverse Shift Lug Lock Screw.............................1
24 Reverse Shift Lug ................................................1
25 4th & 5th Shift Rod..............................................1
26 Mesh Lock Ball ....................................................4
27 Interlock Cross Pin ..............................................1
28 2nd & 3rd Shift Rod.............................................1
29 1st & Reverse Shift Rod ......................................1
30 Mesh Lock Spring................................................3
31 Mesh Lock Spring................................................3
F
CLARK
G
280V-SERIES CONTROL PARTS GROUP (Diecast Cover - Fabricate Rails)
ITEM Description QTY
1 Gear Shift Lever Dust Cover.....................................................1
ITEM Description QTY
16 Front Rail Support................................................................... 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
15 Front Rail Support Capscrew Lockwasher ...............................4
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
Control Top or Remote Control Capscrew4
H
CLARK
I
280V-SERIES CONTROL PARTS GROUP (Diecast Cover - Round Rails)
ITEM Description QTY
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 Welch Plug................................................... 1
9 Shift Rail Housing ........................................ 1
10 1st & Reverse Rocker Lug ........................... 1
11 Shift Fork Lock Pin....................................... 4
12 1st & Reverse Rocker Arm........................... 1
13 4th & 5th Shift Fork...................................... 1
14 2nd & 3rd Shift Fork..................................... 1
15 Mesh Lock Ball............................................. 1
16 1st & Reverse Mesh Lock Spring................. 1
17 1st & Reverse Shift Fork ............................. 1
23 Rear Rail Support .........................................1
24 Rail Support Screw.......................................6
25 Front Rail Support ........................................1
26 2nd & 3rd Shift Rail......................................1
27 Inter-Lock Cross Pin.....................................1
28 1st Gear Shift Stop Space (wide)..................1
29 1st & Gear Shift Lug.....................................1
30 1st & Gear Shift Stop Spacer (narrow) .........1
31 1st & Reverse Shift Rail................................1
32 Mesh & Inter-Lock Ball .................................7
33 Mesh Lock Spring.........................................3
34 Back-up Switch Hole Plug Gasket.................1
35 Back-up Switch Hole Plug ............................1
36 1st & Reverse Latch Plunger Springer Plug .1
37 1st & Reverse Latch Plunger Plug Gasket ....1
38 1st & Reverse Latch Plunger Stop................1
39 1st & Reverse Latch Plunger Spring............1
18 1st & Reverse Shift Fork Rail Lock Pin......... 1
19 1st & Reverse Shift Fork Rail ...................... 1
20 Shift Fork Bushing........................................ 2
21 Shift Fork Bushing........................................ 2
22 4th & 5th Shift Rail....................................... 1
40 1st & Reverse Latch Plunger........................1
41 Control Top Lockwasher...............................4
42 Control Top Screw ........................................4
J
CLARK
K
280V-SERIES BRAKE PARTS GROUP
ITEM Description QTY
ITEM Description QTY
1 Brake Support Capscrew.........................2
2 Brake Support Capscrew.........................2
3 Brake Locating Bracket ...........................1
4 Brake Band Locating Screw Nut..............2
5 Brake Release Spring..............................2
6 Brake Spacer Link Clevis Pin...................2
7 Brake Draw Rod Clevis Pin .....................1
8 Brake Cam Lever.....................................2
9 Brake Adjusting End................................1
10 Brake Draw Rod Clevis Pin Cotter...........1
11 Brake Spacer Link ...................................2
12 Spacer Link Clevis Pin Cotter..................2
13 Adjusting Bolt .........................................1
14 Brake Cam Lever Shoe............................1
15 Brake Band & Facing Assembly (Inc. items
30 & 31)1
18 Companion Flange to Brake Drum Bolt Nut4
19 Anchor Clip Screw ..................................1
20 Brake Compression Spring Washer ........1
21 Brake Adjusting Bolt Nut.........................2
22 Brake Adjusting Bolt Nut Lockwasher .....1
23 Brake Anchor Support Bar ......................1
24 Brake Anchor Clip Spring........................1
25 Brake Support Stud Nut..........................2
26 Brake Support Stud Nut Lockwasher ......2
27 Brake Support Stud.................................1
28 Brake Band Locating Screw ....................1
29 Compression Spring ...............................1
30 Brake Band Facing Rivet .......................26
31 Brake Band Facing .............1Brake Drum1
32 Brake Drum to Flange Bolt ......................4
16 Companion Flange ..................................1
17 Companion Flange to Brake Drum Lock-
washer4
L
280V-SERIES
ASSEMBLY INSTRUCTIONS
When screws with pre-applied thread locking compound
are removed after initial assembly, clean thread locking
compound are removed after initial assembly, clean
threads thoroughly and apply Loctite 262 Thread Lock
before re-installation.
Check all mainshaft constant-mesh gears to make sure
they rotate freely on mainshaft.
Check mainshaft 1st & Reverse sliding gear to make sure
it slides freely on mainshaft.
Hand-spin idler gear and countershaft assemblies after
each is installed on their bearings in trans. case. Both
must spin freely and smoothly.
Unless otherwise specified:
Tighten all capscrews 20-25 Lbs. Ft. [27,2-33,8N.m]
Apply a thin coat of Loctite 510
Gasket Eliminator to the O.D. of all oil seals before
assembly.
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