Eaton FSO-2105 User manual

Introduction
Purpose and Scope of the Manual .................................................................................................................... 1
How to Use this Manual .................................................................................................................................... 1
Warnings and Precautions ................................................................................................................................ 2
Identication ...................................................................................................................................................... 3
Model designation ........................................................................................................................................ 3
Gear Ratio.................................................................................................................................................... 4
Exploded Views................................................................................................................................................. 5
Direct Control Assembly
FSO-2105 / FSO-2505 (4x2 and 4x4) Models ........................................................................................ 5
Shift Yokes and Bars
FSO-2105 / FSO-2505 (4x2 and 4x4) Models ........................................................................................ 6
Transmission Case Assembly
FSO-2105 / FSO-2505 (4x2) Models ...................................................................................................... 7
FSO-2105 / FSO-2505 (4x4) Models ...................................................................................................... 8
Input Shaft / Mainshaft Assembly
FSO-2105 / FSO-2505 (4x2 and 4x4) Models ........................................................................................ 9
Countershaft Assembly
FSO-2105 / FSO-2505 (4x2 and 4x4) Models ...................................................................................... 10
Lubrication Information.................................................................................................................................... 11
Operation......................................................................................................................................................... 13
Gear shift lever pattern............................................................................................................................... 13
Power Flow...................................................................................................................................................... 14
Adhesive and Sealant Application ................................................................................................................... 16
Torque Recommendation ................................................................................................................................ 17
Precautions ..................................................................................................................................................... 19
Troubleshooting............................................................................................................................................... 21
Tool Information............................................................................................................................................... 26
Universal Tools ........................................................................................................................................... 26
Essential Special Tools............................................................................................................................... 27
Complementary Tools................................................................................................................................. 29
Installation Reference...................................................................................................................................... 31
FSO-2105 Model
Application Flex 2.4L SOHC 4x2........................................................................................................... 31
Application Flex 2.4L SOHC 4x4........................................................................................................... 33
FSO-2505 Model
Application Diesel 4x2 2.5 2.8............................................................................................................... 35
Application Diesel 4x4 2.5 2.8............................................................................................................... 37
Application HFV6 4x2............................................................................................................................ 39
Application HFV6 4x4............................................................................................................................ 41
Table of Contents

Gear Shift Lever Housing
Gear Shift Lever Housing Disassembly........................................................................................................... 43
Gear Shift Lever Housing Assembly................................................................................................................ 44
Rear Section
Rear Section Disassembly .............................................................................................................................. 47
Oil Seal Replacement...................................................................................................................................... 52
Rear Section Assembly ................................................................................................................................... 52
Front Section
Front Section Disassembly.............................................................................................................................. 59
Mainshaft
Disassembly.......................................................................................................................................... 61
Assembly............................................................................................................................................... 61
Countershaft
Disassembly.......................................................................................................................................... 65
Assembly............................................................................................................................................... 65
Input Shaft
Disassembly.......................................................................................................................................... 66
Assembly............................................................................................................................................... 66
Shift Yoke Bars
Disassembly.......................................................................................................................................... 67
Assembly............................................................................................................................................... 67
Expansion Plugs
Removal ................................................................................................................................................ 69
Installation ............................................................................................................................................. 70
Permaglide Bushing
Removal ................................................................................................................................................ 70
Installation ............................................................................................................................................. 71
Reverse Shifting Interlocking System
Description ............................................................................................................................................ 71
Disassembly.......................................................................................................................................... 72
Assembly............................................................................................................................................... 72
Double Gear Shifting Interlocking System
Description ............................................................................................................................................ 73
Disassembly.......................................................................................................................................... 74
Assembly............................................................................................................................................... 74
Table of Contents

Input Shaft Bearing Cup
Removal ................................................................................................................................................ 75
Installation ............................................................................................................................................. 75
Input Shaft Oil Bafe and Oil Seal
Removal ................................................................................................................................................ 76
Installation ............................................................................................................................................. 76
Countershaft Front Bearing Cup
Removal ................................................................................................................................................ 77
Installation ............................................................................................................................................. 77
Mainshaft and Countershaft Rear Bearing Cups
Removal ................................................................................................................................................ 78
Installation ............................................................................................................................................. 78
Synchronizer Assemblies
Description ............................................................................................................................................ 79
1st/2nd Speed Synchronizer ................................................................................................................. 79
3rd/4th Speed Synchronizer.................................................................................................................. 81
5th/Reverse Speed Synchronizer ......................................................................................................... 83
Front Section Assembly................................................................................................................................... 84
End Play Adjustment
Mainshaft End Play Measurement ........................................................................................................ 88
Countershaft End Play Measurement ................................................................................................... 89
Determining Shim Pack Thickness for End Play Adjustment ................................................................ 89
Table of Contents

Introduction
Introduction
1
Purpose and Scope of the Manual
This manual is designed to provide detailed information necessary to service and repair Eaton® transmissions
FSO-2105 and FSO-2505.
How to Use this Manual
Disassembly and assembly instructions in this manual make use of a typical FSO-2105 or FSO-2505
transmission. Provided illustrations and pictures show parts that may differ from one transmission model to
another, according to its application and serial number.
In addition, it is also assumed in the manual that the transmission has been removed from the vehicle and the
lubricant has been drained.
The manual has been divided into two main groups as follows:
1. Information and technical references, placed all together into one section.
2. Disassembly and assembly instructions, by its turn, divided into sections gathering specic component
assemblies.
For the complete disassembly and assembly of the transmission, follow the manual in its natural sequence.
However, if only a component should be serviced, locate in the index the section to which the component
belongs and the page number referring to it.
For more detailed information on product improvement, repair procedures and other subjects related to service,
please contact:
Eaton Ltda. – Transmission Division
After Sales & Service Support
Rua Clark, 2061 – PO Box 304
13270 - Valinhos - São Paulo - Brazil
Phone: [phone]
Fax: [phone]
WARNING! Eaton reserves the right to make modications in its products and to change specications included
in this manual at any time without previous notice.

Warnings and Precautions
2
Warnings and Precautions
WARNING
Before starting a vehicle always be seated in the driver’s seat, place the transmission in neutral, set the
parking brakes and disengage the clutch.
Before working on a vehicle place the transmission in neutral, set the parking brakes and block the
wheels.
Before towing the vehicle place the transmission in neutral, and lift the rear wheels off the ground, or remove the
axle shafts, or disconnect the driveline to avoid damage to the transmission during towing.
The description and specications contained in this service publication are current at the time of printing.
Eaton Corporation reserves the right to discontinue or modify its models and/or procedures and to change
specications at any time without notice.
Any reference to brand name in this publication is made as an example of the types of tools and materials
recommended for use and should not be considered an endorsement. Equivalents may be used.
This symbol is used throughout this manual to call attention to procedures where carelessness or
failure to follow specic instructions may result in personal injury and/or component damage.
Departure from the instructions, choice of tools, materials and recommended parts mentioned in this publication
may jeopardize the personal safety of the service technician or vehicle operator.
WARNING: Failure to follow indicated procedures creates a high risk of personal injury to the servicing
technician.
Caution: Failure to follow indicated procedures may cause component damage or malfunction.
Note: Additional service information not covered in the service procedures.
Tip: Helpful removal and installation procedures to aid in the service of this unit.
Always use genuine Eaton replacement parts.

Identication
Identication
3
FSO-2105/01
Model designation
All Eaton transmissions are identied by the model designation and serial number. This information is stamped
on the identication plate xed to the transmission case.
Eaton
Synchronized
Overdrive
FSO - 2 105A
Gear ratio
Forward speeds
Design level
Nominal torque capacity
(x100 Lb.ft)
WARNING! Do not remove or destroy the transmission identication plate.
Note: When ordering replacement parts or calling for service support, please inform identication plate numbers.

Identication
4
Ratio: Gear ratio. It is calculated by dividing the number of teeth in driven gear by the number of teeth in drive
gear, and then multiplying by the input gear pair ratio.
Example:
FSO-2105
Input pair: Input shaft = 26 teeth; = 37 teeth => 37/26 = 1.423 ~
First gear: Countershaft = 14 teeth; Mainshaft = 44 teeth => 44/14= 3.143 ~
1.423 x 3.143 = 4.472 ~
FSO 2105 FSO 2505
A A B
Torque N.m 270 440 440
Lb.ft 200 325 325
ND Ratio ND Ratio ND Ratio
Input shaft 26 26 26
Countershaft 37 37 37
1st (CE)
(EP)
14
44 4.47 15 43 4.08 15 43 4.08
2nd (CE)
(EP)
22
38 2.46 23 37 2.29 23 37 2.29
3rd (CE)
(EP)
29
30 1.47 29 30 1.47 29 30 1.47
4th (CE)
(EP)
-
-1.00 - -1.00 - -1.00
5th (CE)
(EP)
45
26 0.82 53 27 0.72 51 29 0.81
Reverse (CE)
(RV)
(EP)
12
29
32
3.79
12
29
32
3.79
12
29
32
3.79
ND =Number of teeth in gear
CE = Countershaft
EP = Mainshaft
RV = Reverse idle gear
Gear Ratio

Exploded Views
Exploded Views
5
FSO-2105/explo5
Direct Control Assembly
FSO-2105 / FSO-2505 (4x2 and 4x4) Models
1. Gear shift lever housing
2. Threaded pin
3. Locating pin
4. Spring
5. Threaded plug
6. Gear shift lever pivoting
support
7. Thrust washer
8. Boot
9. Gear shift lever
10. Pivot pin
11. Gear shift lever bushing
12. Shock-absorbing rubber
gasket
13. Flat washer
14. Support spacer
15. Shock-absorbing bushing
16. Washer
17. Screw M8 x 35

Exploded Views
6
Shift Yokes and Bars
FSO-2105 / FSO-2505 (4x2 and 4x4) Models
30. 3rd/4th speed shift yoke
assembly
31. Yoke pads
32. Roll pin
33. 3rd/4th speed shift block
34. Roll pin
35. 3rd/4th speed yoke bar
36. Ball
37. Ball
38. Spacer pin
39. 1st/2nd speed yoke bar
40. 1st/2nd speed shift yoke
assembly
41. Yoke pads
42. Roll pin
43. Shift selector block assembly
44. Bushing
45. Pin
46. Washer
47. Spring
48. Spring support
49. Snap ring
50. Shift selector bar (main bar)
51. Shift lug (4x4)
51a. Shift lug (4x2)
52. Roll pin
53. 5th/reverse speed shift
block
54. Roll pin
55. 5th/reverse speed yoke bar
56. 5th/reverse speed shift
block
57. Roll pin
58. 5th/reverse speed shift
yoke
59. Swivel holder
60. Yoke pads
FSO-2105/explo4

Exploded Views
Exploded Views
7
Transmission Case Assembly
FSO-2105 / FSO-2505 (4x2) Models
70. Front housing
71. Oil seal
72. Screw
73. Plug
74. Bearing
75. Dowel pin
76. Oil bafe
77. Plug
78. Reverse lock spring
79. Cup plug
80. Roll pin
81. Reverse lock assembly
82. Intermediate housing
83. Filling plug
84. Threaded pin
85. Screw
86. Dowel pin
87. Screw
88. Harness bracket
89. Reverse light switch
90. Ball
91. Lock spring
92. Threaded plug
93. Drain plug
94. Bracket
95. Rear housing
96. Oil seal
97. Actuator’s bushing
98. Actuator
99. Actuator’s spring
100. Threaded plug
101. Magnetic speed sensor
102. Screw
103. Oil pick-up
104. Reverse idle gear shaft
105. Needle bearing
106. Reverse idle gear
107. Bearing
108. Shifting guide
109. Screw
110. Bracket
111. Bracket
FSO-2105/explo1

Exploded Views
8
Transmission Case Assembly
FSO-2105 / FSO-2505 (4x4) Models
FSO-2105/explo1a
70. Front housing
71. Oil seal
72. Screw
73. Plug
74. Bearing
75. Dowel pin
76. Oil bafe
77. Plug
78. Reverse lock spring
79. Cup plug
80. Roll pin
81. Reverse lock assembly
82. Intermediate housing
83. Filling plug
84. Threaded pin
85. Screw
86. Dowel pin
87. Screw
88. Harness bracket
89. Reverse light switch
90. Ball
91. Lock spring
92. Threaded plug
93. Drain plug
94. Rear housing
95. Oil seal
96. Actuator’s bushing
97. Actuator
98. Actuator’s spring
99. Threaded plug
100. Oil pick-up
101. Reverse idle gear shaft
102. Needle bearing
103. Reverse idle gear
104. Bearing
105. Shifting guide
106. Screw
107. Bracket
108. Bracket

Exploded Views
Exploded Views
9
Input Shaft / Mainshaft Assembly
FSO-2105 / FSO-2505 (4x2 and 4x4) Models
120. Input shaft bearing cup
121. Input shaft bearing cone
122. Input shaft
123. 4th speed synchronizer cone
124. Snap ring
125. 4th speed synchronizer ring
126. Mainshaft front bearing cone
127. Snap ring 2.175 mm
127. Snap ring 2.250 mm
127. Snap ring 2.325 mm
128. 3rd/4th speed synchronizer
assembly
129. Spring
130. Key
131. 3rd speed synchronizer ring
132. Mainshaft 3rd speed gear
cone
133. Mainshaft 3rd speed gear
134. Needle bearing
135. Mainshaft (4x2)
135a. Mainshaft (4x4)
136. Needle bearing
137. Mainshaft 2nd speed gear
138. Mainshaft 2nd speed gear
cone
139. 1st/2nd speed synchronizer
inner ring
140. 1st/2nd speed synchronizer
middle ring
141. 1st/2nd speed synchronizer
outer ring
142. 1st/2nd speed synchronizer
assembly
143. Key
144. Mainshaft 1st speed gear
145. Needle bearing
146. Bushing
147. Mainshaft intermediate
bearing cone
148. Mainshaft intermediate
bearing cup
149. Shim 0.050 mm
149. Shim 0.102 mm
149. Shim 0.178 mm
149. Shim 0.254 mm
149. Shim 0.508 mm
149. Shim 0.762 mm
149. Shim 1.016 mm
150. Mainshaft 5th speed gear
151. Spacer
152. Mainshaft reverse speed gear
153. Ball bearing
154. Nut
155. Ball (4x2)
156. Speedometer rotor (4x2)
157. Snap ring (4x2)
FSO-2105/explo2

Exploded Views
10
FSO-2105/explo3
Countershaft Assembly
FSO-2105 / FSO-2505 (4x2 and 4x4) Models
160. Countershaft front bearing
cup
161. Countershaft front bearing
cone
162. Countershaft
163. Countershaft intermediate
bearing cone
164. Countershaft intermediate
bearing cup
165. Shim 0.050 mm
165. Shim 0.102 mm
165. Shim 0.178 mm
165. Shim 0.254 mm
165. Shim 0.508 mm
165. Shim 0.762 mm
165. Shim 1.016 mm
166. Ball
167. 5th speed gear thrust washer
168. Needle bearing
169. Countershaft 5th speed gear
170. 5th speed synchronizer ring
171. 5th/reverse speed
synchronizer assembly
172. Spring
173. Key
174. Snap ring 2.215 mm
174. Snap ring 2.365 mm
174. Snap ring 2.290 mm
175. Countershaft reverse speed
gear synchronizer ring
176. Needle bearing
177. Countershaft reverse speed
gear
178. Ball
179. Thrust washer
180. Ball bearing
181. Snap ring

Lubrication Information
Lubrication Information
11
Highway use
After rst 50,000 km Change transmission oil
Every 100,000 km Change transmission oil
Off-highway use
After rst 50,000 km Change transmission oil
Every 50,000 km Change transmission oil
Lubrication
Proper lubrication procedure is the key to a good and complete maintenance program. If the oil is not doing its
job, or if the oil level is ignored, all the other possible maintenance procedures will not be enough to keep the
transmission running or to assure long transmission life.
Eaton transmissions are designed so that all the internal parts operate in an oil circulating bath, created by the
motion of gears and shafts. Thus, all parts are properly lubricated if these procedures are closely followed:
1. Maintain proper oil level by inspecting it regularly.
2. Change oil regularly following the maintenance interval chart.
3. Use the recommended grade and type of oil.
4. Buy from a reputable dealer.
Oil change and level inspection
Periodic transmission oil change eliminates possible bearing failures, ring wear and seizures, since the products
of normal wear in service (tiny metal particles), which circulate in the transmission oil, are harmful to these parts.
In addition, the oil changes chemically due to the repeated heating and cooling cycles of a transmission in use.
As a general guide, the following chart provides maintenance interval recommendation to level inspection and oil
change.
WARNING! Always follow the vehicle manufacturer maintenance recommendation, which prevails over this
chart.
Recommended lubricant oil: Eaton PS - 267
Trademarks: Eaton LCC2 – 3348887

Lubrication Information
12
Draining
Drain transmission oil while the oil is warm. To drain
oil, remove the magnetic drain plug.
Clean the drain plug before re-installing it.
Relling
FSO-2105/02
Clean case area around oil ller plug, remove the
plug and rell the transmission until lubricant is level
with the bottom of the ller plug hole.
Note: The amount of oil varies with the position of
vehicle related to the ground and the installation
angle of transmission. Before relling, place vehicle
on a at and level surface. Fill up transmission until
lubricant begins to leak through the ller plug.
Lubricant oil volume: 2.7 to 3.3 liters
Correct Oil Level
Incorrect Oil Level
Oil level inspection
Before checking oil level, clean case area around
ller plug and if necessary, add enough oil to maintain
the proper oil level.
WARNING! Do not mix lubricant of different types
and brands, as this may cause incompatibility issues.

Operation
Operation
13
Gear shift lever pattern
FSO-2105/03
FSO-2105 and FSO-2505 transmissions have 5
forward speeds and one reverse speed, all of them
synchronized.
To shift speeds, follow the shift pattern shown by the
illustration on the side.
A reverse gear shifting interlocking system prevents
from accidental transmission shifting from 5th to
reverse gear.
Tips for the driver
Always use the clutch to change gears. The incorrect
use of the clutch may cause premature failures of the
synchronizer assembly.
Always select a starting gear that will provide
sufcient power (torque) for the vehicle’s load and
working conditions (terrain).
Never slam or jerk the gear shift lever to complete
gear engagement.
Never leave the shift lever in the neutral position
while going downhill.

Power Flow
14
Power Flow
The transmission must efciently transfer the engine’s
power or torque to the vehicle’s driveline.
It is essential to know what takes place in
the transmission during torque transfer when
troubleshooting or making repairs.
1st, 2nd and 3rd Speeds
1. Torque from the engine is transferred to the
transmission’s input shaft.
2. From input shaft, the torque is transferred to the
countershaft drive gear. In this way, input shaft
and countershaft always run together.
3. The torque along the countershaft is delivered
to all mainshaft gears assembled on bearings.
These gears rotate free unless one gear is
shifted.
4. When a gear is shifted, the torque is transferred
from the corresponding engaged mainshaft gear,
through the clutching teeth of the synchronizer
assembly, to the mainshaft. Torque is, then,
delivered along the mainshaft to the driveline
components through output yoke.
Fluxo
1st Speed
1
2
34
Fluxo_1
2nd Speed
Fluxo_2
3rd Speed
Fluxo_3

Power Flow
Power Flow
15
4th Speed
The 4th speed gear is also named direct speed gear.
1. Torque from the engine is transferred to the
transmission’s input shaft that, despite driving
the countershaft at the same time, transfers the
torque directly to the mainshaft. The input shaft
clutching teeth engage the clutching teeth of the
4th speed synchronizer unit which transfers the
torque to the mainshaft.
The transmission’s noise level in this speed is much
reduced, since torque is delivered directly from one
shaft to another and there are no gears under load.
5th and Reverse Speed
The 5th and reverse speed gears synchronizer unit
is assembled on the countershaft, unlike the other
speed synchronizers that are assembled on the
mainshaft. By its turn, their corresponding gears on
mainshaft are assembled xed to the mainshaft.
1. With the 5th speed gear engaged, torque is
transferred from countershaft to the mainshaft
corresponding gear through the clutching teeth of
the synchronizer hub.
2. When the reverse speed gear is engaged, torque
is transferred from countershaft to the reverse
idler gear, which changes the rotating direction,
and then, from that gear to the mainshaft’s
reverse speed gear.
4th Speed
Fluxo_4
5th Speed
Fluxo_5
Reverse Speed
Fluxo_re