Dover TWG 250PR Operating instructions

www.team-twg.com
SEL-0152-000
REV 1 JUNE 2015
Model 250PR
Service/Repair Manual
TABLE OF CONTENTS
SAFETY NOTES...........................................................................................................................................2
INTRODUCTION AND THEORY OF OPERATION .....................................................................................3
HYDRAULIC SCHEMATIC...........................................................................................................................4
MAINTENANCE AND SERVICE ..................................................................................................................5
TWG 250PR RECOMMENDED OILS ..........................................................................................................6
OIL CHANGE................................................................................................................................................7
DISASSEMBLY ............................................................................................................................................8
ASSEMBLY ..................................................................................................................................................9
SERVICING THE BRAKE...........................................................................................................................10
SERVICING THE BEARING AND PINION SECTION................................................................................12
SERVICING THE PLANETARY SETS.......................................................................................................13
TROUBLESHOOTING................................................................................................................................14
TORQUE SPECIFICATIONS CHART ........................................................................................................15
BILL OF MATERIAL...................................................................................................................................16
CROSS SECTIONAL ASSEMBLY DRAWING ..........................................................................................17
EXPLODED ASSEMBLY DRAWING.........................................................................................................18
INSTALLATION DRAWING........................................................................................................................19

2
SAFETY NOTES
FAILURE TO HEED THE FOLLOWING WARNINGS MAY
RESULT IN SERIOUS INJURY OR DEATH!
•Operators/Technicians must be trained in the proper, safe operation of the swing-drive gearbox.
•All shields and guards must be in place during operation of swing-drive gearbox.
•Be aware of and stay clear of all pinch points during operation of swing-drive gearbox.
•Boom must be stowed and properly secured while removing swing-drive gearbox.
•Avoid shock loads. This type of load could impose a torque many times the actual torque rating
of the swing-drive gearbox.
•Make sure that all equipment, including the swing-drive gearbox is maintained properly.
•Counterbalance valves are pre-set from the factory and must not be adjusted.

3
INTRODUCTION AND THEORY OF OPERATION
The TWG 250PR planetary gearbox is a hydraulically driven 2-stage planetary gearbox designed to
use a motor with SAE “A” 2-BOLT mount and 1.00” 6B spline shaft. This gearbox has a total ratio of
38:1.
The gearbox is designed to utilize a hydraulic motor, driving through a multiple-disc static oil brake,
into a pair of planetary gear sets to the output pinion.
The multiple-disc oil bath static park brake is spring applied and hydraulically released through a
port in the brake housing. The multiple-disc “service brake” is hydraulically applied through a port
in the brake housing.
During operation, dual counterbalance valves are used for dynamic braking to prevent the gearbox
from moving faster than desired. These counterbalance/brake valves partially block the main line
from the motor back to the directional control valve, allowing only a limited amount of hydraulic
fluid through the motor. The counterbalance valves are generally internally modulated by sensing
pressure on the supply line. Additionally, any time there is sufficient pressure to modulate the
counterbalance valves; this same pressure releases the static friction/stator style park brake.

4
HYDRAULIC SCHEMATIC
The TWG 250PR is equipped with a spring applied hydraulically released static “park brake” and an
optional integral hydraulically applied dynamic “service brake”. The park brake on this unit should
full release by pressurizing the “BR” port to 300 psi. The maximum pressure allowed into the park
brake is 3,000 psi. The service brake is applied by pressurizing the “BA” port while pressurizing the
“BR” port. The maximum pressure allowed into the service brake port is 1,000 psi. The service
brake can be cooled using a flow-thru cooling method by plumbing hydraulic oil into “BC IN” port
and plumbing “BC OUT” port back to tank. The maximum pressure allowed in the brake cavity (flow
thru cooling circuit) is 25 psi. Excessive pressure in the flow thru cooling circuit could damage the
oil seal separating the brake oil from the gearbox oil.

5
MAINTENANCE AND SERVICE
For safe and consistent operation of TWG hoists, gearboxes, and winches, a regular program of
preventive maintenance is strongly recommended. Regular oil changes with the correct oil and
frequency for the application and an annual inspection of the wear components will help ensure
a long life for your planetary geared products.
Maintenance Scheduling
Manufacturer recommends changing oil after first 50 hours of operation. All gearboxes require
the proper EP gear oil for lubrication. Some units may be equipped with a grease fitting for
lubrication of the output shaft bearings (pinion up applications). The shaft bearings should be
greased sparingly at every 50 operating hours with an EP lithium or GP bearing lube. For pinion
down applications, gearbox oil will lubricate shaft bearings
Oil Level Maintenance
Tulsa Winch recommends that the oil be checked and adjusted as part of the pre-use
inspection. If the oil level drops frequently or oil leakage is detected during an inspection,
maintenance should be performed to correct any problems.
Oil Change Interval
The oil in the gearbox and brake sections (if applicable) should be changed every 1000 hrs or
6 months of usage.

6
TWG 250PR RECOMMENDED OILS
Choose the proper gearbox and brake oil from lists below.
FOR STANDARD TEMP APPLICATIONS -10˚F THRU 180˚F (-23˚C THRU 82˚C) oil temp.
*Gearbox oil (GL-5): API 80W/90 GL-5 (Or equivalent)
Super MP 75W-90 GL-5 (Original oil in unit from factory)
Century Unigear Semi-Synthetic 80W-90
Texaco Multigear SS 80W-90 GL-5
Chevron DELO 80W-90 GL-5
**Brake oil: Not applicable for this gearbox
FOR LOW TEMP APPLICATIONS -40˚F THRU 180˚F ( -40˚C THRU 82˚C) oil temp.
*Gearbox oil (GL-5): Mobil Delvac Synthetic 75W90 (Or equivalent)
Mobil Mobilube 1 SHC 75W90
CITGO, Syntetic Gear Lube 75W-90
Eaton, Roadranger EP75W-90
Mobil, Mobilube SHC 75W-90
Shell, Spirax® S 75W-90
Sunoco®, Duragear EP75W-90
Petro-Canada, Traxon E Synthetic 75W-90
**Brake oil: Not Applicable for this gearbox
*All gearbox oils must meet MIL-PRF2105 and GL-5 specifications.
** Brake oil is not applicable to units equipped with the “Flow Thru Brake Cooling” option.
Hydraulic oil is plumbed thru the brake on “Flow Thru Brake Cooling” option.
GEARBOX OIL CAPACITY
PINION UP
N/A
PINION DOWN
3.50 QTS
The hydraulic system should use only high quality hydraulic fluid from reputable suppliers. These
oils should contain additives to prevent foaming and oxidation in the system. The hydraulic system
should be equipped with a return line filter capable of filtering 10 micron particles from the system.

7
OIL CHANGE
Gearbox oil is drained by removing the drain plug and vent. Examine the used oil for signs of
significant metal deposits and then dispose of it in a proper manner.
Replace the drain plug. Fill the swing drive with the appropriate amount and type of oil and then
replace plug and vent. See page 6 of this manual for the recommended oil type, amount and grade
for your application.
Gearbox oil level inspection is achieved by removing the dipstick and visually inspecting the oil level.

8
DISASSEMBLY
1. Remove the gearbox from the crane by securing the boom, removing the 20 mounting bolts
and any hydraulic hoses connecting the crane to the gearbox assembly.
2. Orient the gearbox vertical and drain the gear oil from the gearbox. See page 7 of this
manual.
3. Label and disconnect all hoses still attached to the gearbox.
4. Remove the hydraulic motor by removing the 2 bolts in the motor flange.
5. Remove the brake assembly from the gearbox by removing 20 bolts and washers (Item
16, 15). NOTE: Notice the orientation of the ports in relation to the drain and fill holes for
reassembly. See Servicing The Brake section on page 10 for brake service or repair .
6. Inspect the O-ring (Item 44) for damage and replace if necessary.
7. Remove the nylon thrust washer (Item 14) and sun gear (Item 13) from the input
planetary set (Item 11). Inspect for wear or damage and replace if needed.
8. Remove input planet gear assembly by pulling straight up and out of the ring gear (Item
12). See Servicing The Planetary Set section on page 13 for disassembly and repair.
9. Remove the nylon thrust washer (Item 14) and sun gear (Item 18) from the output
planetary gear set (Item 10). Inspect for wear or damage and replace if needed.
10. Remove output planet gear assembly by pulling straight up and out of the ring gear
(Item 12). See Servicing The Planetary Set section on page 13 for disassembly and
repair.
11. To service the pinion gear or pinion bearings see Servicing The Pinion Gear/Bearings
section on Page 12 of this manual for disassembly and repair.
44 11 1213
14
18
19
27

9
ASSEMBLY
1. After servicing, inspecting and or repairing the Brake, Pinion Bearing and or the Planetary
Gear sub-assemblies start reassembly by positioning the Bearing/Pinion section in a pinion
down orientation.
2. Install new O-ring (Item 43) onto ring gear pilot on top of bearing housing (Item 1).
3. Next install the ring gear (Item 12) onto the bearing housing making sure to align dowel
pins with the appropriate dowel pin hole. Using a dead blow hammer tap ring gear into
position.
4. Insert the output planetary gearset (Item 10) into the ring gear making sure that it fully
engages the splines on the output pinion shaft (Item 2).
5. Install output sun gear (item 18) into output planet set (Item 10).
6. Place and center nylon thrust washer (Item 14) on top of output planet set (Item 10).
7. With nylon washer in place install the input planet set (Item 11) into the ring gear making
sure it fully engages the teeth on the output sun gear (Item 18).
8. Insert the input sun gear (Item 13) into the input gear set (Item 11). Turn sun gear by
hand to ensure the gearing rotates and is not bound up.
9. Place and center nylon thrust washer (Item 14) onto input planet set (Item 11).
10. Lubricate and install a new O-ring (Item 43) onto brake housing (Item 27).
11. While considering proper port orientation install the brake section sub-assembly onto ring
gear (Item 12) and input sun gear (Item 13).
12. Install the 20 ring gear bolts and washers (Items 15 and 16). Tighten to spec. See page 15
for Torque Specifications Chart.

10
SERVICING THE BRAKE
1. Evenly remove the six bolts (Item 26) attaching the brake housing (Item 27) to the brake
adapter (Item 19). Spring pressure will raise the brake housing as the bolts are loosened.
Remove the brake housing from the brake adapter.
2. Remove the piston (Item 28) from the brake housing (Item 27) by applying shop air to the
“BR” port.
3. Remove the brake shaft (Item 30), friction disc’s (Item 31), stator plates (Item 32) and
bearings (Item 29) from brake housing (Item 27).
4. Using a bearing puller remove the bearings (Item 29) from the brake shaft (Item 30).
5. Remove the friction disc’s (Item 31) and stator plates (Item 32) from brake shaft (Item 30)
and check them for excessive wear, then replace if necessary. Friction discs should measure at
least 0.075 inches thick and stator plates should at least than 0.045 inches thick.
6. Remove the spacer (Item 40).
7. If equipped with a “Service Brake”, remove the service brake piston by applying shop air to the
“BA” port.
8. Remove and inspect all brake springs (Item 25) for damage. Replace if necessary.
9. Remove the O-rings (Item 44) out of brake adapter (Item 19).
10. Remove the O-rings and backup rings (Items 45, 46, 47, 48) from the piston brake (Item
28).
11. Install a new bearing (Item 29) into the brake adapter (Item 19).
12. Install the brake springs (Item 25) into the spring pockets in brake adapter (Item 19).
13. Tap or press the brake shaft (Item 30) into the bearing in the brake adapter (Item 19).
Note: The 6 tooth spline should be oriented to engage with the hydraulic motor.
14. Install the O-ring (Item 44) onto the brake adapter (Item 19).
15. Install the O-ring and backup rings (Items 45, 46, 47 and 48) onto the O.D. and I.D. of the
piston brake. Note, the rectangular backup rings should be located on the outsides of the O-
rings as shown in the cross sectional drawing on the Pg. 11 of this manual. Lubricate the O-
ring and backup rings and place the piston onto the springs centering the piston in the brake
adapter.
16. Install the friction discs (Item 31) and stator plates (Item 32) into the piston over the brake
shaft (Item 30). Note, you will start with a friction disc and end with a friction disc.
17. Place the spacer (Item 40) into the piston on top of the friction/stator pack.

11
18. Carefully place brake housing assembly onto the piston ensuring to orient the motor mount
bolts and all ports properly. Ensure the dowel pin (Item 34) is installed through the brake
housing, brake piston and brake adapter. Tap brake housing down until it makes contact
with the springs.
19. Install the six bolts (Item 26) thru the brake housing into the brake adapter (Item 19) and
evenly tighten the bolts to draw the brake housing down onto the springs to prevent damaging
the O-ring and backup rings on the brake piston.
20. Tighten to spec. See page 15 for Torque Specifications Chart.
43
44
48
47
46
45 1113
14
19
22
25
27
28
29
29
30
27
40

12
SERVICING THE BEARING AND PINION SECTION
1. Remove the gearbox from the vehicle by removing the bolts in the mounting flange (Item 9).
2. Remove the brake sub-assembly, gear sets (Items 10 and 11), and ring gear (Item 12) from
unit by removing the twenty ring gear bolts and washers (Items 15 and 53). Note or mark the
orientation of the brake housing in relation to the gearbox oil drain port located in the bearing
housing (Item 1) for re-assembly.
3. Pry the oil seal (Item 42) out of the bearing housing (item 1) and using tin snips cut the seal
and remove it from the output pinion gear (Item 2).
4. Remove the retaining ring (Item 7) from the bearing housing (Item 1).
5. Next secure the bearing housing assembly and press the pinion gear (Item 2), spherical bearing
(Item 4), retaining ring (Item 8) and spacer (Item 6) out of the bearing housing (Item 1).
6. Remove the retaining ring (Item 7) from bearing housing.
7. Tap or press the ball bearing (Item 5) out of the bearing housing.
8. Clean and inspect all parts and hardware for damage or wear and replace if necessary.
9. For re-assembly of the bearing and pinion section the distance of the mounting flange to the
end of the pinion must be maintained while pressing the new bearings into the housing. For this
unit this dimension is 7.750”. See Image below for reference.
10. Install outboard retaining ring (Item 7) into bearing housing.
11. Install new oil seal (Item 42) into bearing housing (item 1).
12. Carefully place bearing housing ass’y onto pinion shaft
making sure to have the appropriate spacers in place to
achieve the 7.750” dim. shown in this illustration.
13. Using appropriate press tooling install and press the
spherical roller bearing (Item 4) into the housing.
14. Install retaining ring (Item 8) onto pinion shaft making
sure it is seated properly in groove.
15. Next insert bearing spacer (Item 6) into housing.
16. Using proper press tooling press the ball bearing (Item 5)
into the housing.
17. Install inboard retaining ring (Item 7) into the housing.
18. Check sub-assembly to ensure the pinion rotates freely.

13
SERVICING THE PLANETARY SETS
The TWG 250PR planetary gear sets (Items 10 and 11) are not serviceable in the field. Replace as a
unit. Inspect for any damage or wear and replace if necessary.

14
TROUBLESHOOTING
GEARBOX BRAKE WON’T HOLD
Possible Solutions:
1. The brake discs and or stator plates are worn. Friction discs should measure no less than
0.075 inches thick and the stator plates should measure at least 0.045 inches thick and
replace as necessary
2. Broken dowel pins in brake piston (Item 34). Check and replace if necessary
3. Mechanical failure. Evaluate all parts that transmit torque to ensure structural integrity and
replace any parts that show signs of damage or excessive wear
4. Weak or damaged brake springs. Free length of springs should be 1.000”
GEARBOX UNABLE TO ROTATE
Possible Solutions:
1. Motor failure. Remove motor and rotate both directions verifying pressure rotating in both
directions is appropriate.
2. Gearing Failure. See page 13 for servicing the planetary gear sets
3. One of the counterbalance valve cartridges may have a plugged metering
hole . Remove the counterbalance cartridge valves and inspect/clean metering holes
Le to lower load
OIL LEAKS FROM VENT
Possible Solutions:
1. The brake piston O-rings may have failed. Service the brake section and replace any worn
or damaged parts and O-rings found
2. Hydraulic motor shaft seal failure. Return to an authorized dealer for service
3. Gearbox is overfilled with oil. Maintain proper oil amount
4. Brake oil seal failure. Inspect and replace oil seal

15
TORQUE SPECIFICATIONS CHART
Dry
Plated
Lubricated
Dry
Plated
Lubricated
SAE
Grade 5
SAE
Grade 5
SAE
Grade 5
SAE
Grade 8
SAE
Grade 8
SAE
Grade 8
Nominal
Size
Torque
*(Ft-Lbs)
Torque
*(Ft-Lbs)
Torque
*(Ft-Lbs)
Torque
*(Ft-Lbs)
Torque
*(Ft-Lbs)
Torque
*(Ft-Lbs)
¼
20
8
6
5
12
9
7
¼
28
10
7
6
14
10
8
5/16
18
17
13
10
25
18
15
5/16
24
19
14
11
27
20
16
3/8
16
31
23
19
44
33
26
3/8
24
35
26
21
49
37
30
7/16
14
49
37
30
70
53
42
7/16
20
55
41
33
78
58
47
½
13
76
57
45
106
80
64
½
20
85
64
51
120
90
72
9/16
12
109
82
65
153
115
92
9/16
18
122
91
73
172
129
103
5/8
11
150
113
90
212
159
127
5/8
18
170
128
102
240
180
144
¾
10
266
200
160
376
282
226
¾
16
297
223
178
420
315
252
7/8
9
430
322
258
606
454
364
7/8
14
474
355
284
668
501
401
1
8
644
483
386
909
682
545
1
14
721
541
433
1019
764
611
1-1/8
7
794
596
475
1288
966
772
1-1/8
12
890
668
534
1444
1083
866
1-1/4
7
1120
840
672
1817
1363
1090
1-1/4
12
1241
930
745
2012
1509
1207
T = BOLT TORQUE (LB. FT.) T = (KWD) / 12
K = TORQUE COEFFICIENT (K = 0.20 DRY K = 0.15 PLATED K = 0.12 LUBRICATED)
W = PRELOAD TENSION
D = NOMINAL BOLT SIZE (IN.) * ALL TORQUE VALUE TOLERANCES ARE ± 5%

16
BILL OF MATERIAL
Item
Part Number
Description
Qty./Parent
10
45558
HOUSING, BEARING, 250PR
1
20
45554
SHAFT, OUTPUT, PINION, 250PR
1
40
45571
BEARING, SPHERICAL
1
50
29967
BEARING, BALL
1
60
45559
SPACER, BEARING, 250PR
1
70
45572
RING, RETAINING
2
80
45573
RING, RETAINING
1
90
45553
FLANGE, MOUNTING, PLR250
1
100
4610
GEARSET, OUTPUT, 250PR
1
110
4611
GEARSET, INPUT, 38:1, 250PR
1
120
45646
GEAR, RING, 250PR
1
130
45568
GEAR, SUN, INPUT, 31:1 & 38:1, 250PR
1
140
13929
WASHER-THRUST-NYLON-4 1/4 OD X 1/4T>
2
150
41000
LOCKWASHER, HI-COLLAR
20
160
45551
CAPSCREW-SH-1/2-13UNC X 6 1/2
20
170
41024
CAPSCREW-SH-1/2-13UNC X 1 3/4
20
180
45648
GEAR, SUN, OUTPUT, 250PR
1
190
45651
ADAPTER, BRAKE, 250PR
1
200
42392
PLUG, SOCKET HEAD, ORING, 9/16-18
1
210
41719
PLUG, O-RING
4
220
33561
PROTECTOR
1
230
23543
CAPSCREW-HH-1/2-13UNC X 3/4-GR 5
2
240
13050-TW
BREATHER
1
250
2319
SPRING-COMP-3/4D*1#HP BRAKE
12
260
1376
CAPSCREW-HH-7/16-14UNC X 2 1/2-GR 8
6
270
45580
HOUSING, BRAKE, 250PR
1
280
12377
PISTON-BRAKE-NONBAL-DP
1
290
81434
BEARING-BALL-1 3/4 ID-FAFNIR-9109K
2
300
11688
SHAFT-BRAKE
1
310
46245
DISC, FRICTION
3
320
3159
PLATE-DRIVE-BRAKE-MICO-C-P/N 32-230-045
2
330
29043
RING, RETAINING
1
340
3263
PIN-DOWEL-5/16 X 3 1/2
2
350
41307
PLUG, SOCKET HEAD, ORING, 7/16-20
1
360
42752
FITTING, ADAPTER SHORT BODY
1
370
545-10052-1
PIN, DOWELL 1/2X1
3
380
29931
O-RING, -906
1
390
939487
PLUG, O-RING
1
400
45549
SPACER, BRAKE, 250PR
1
410
45700
DIPSTICK, 180PR
1
420
45574
SEAL, OIL
1
430
9736
ORING-9 3/4ID*1/8W-#273-BUNA N-70D
2
440
9844
ORING-6 3/4 ID X 7 OD X 1/8 W-#2-261
1
450
9853
ORING-6 1/2ID X 3/16W-#2-363-BUNA N-70D
1
460
9854
RING-BACKUP-6 1/4 ID X .183W-#8-362
1
470
9851
ORING-5 3/8 ID X 3/16 W 2-356 BUNA 70
1
480
9852
RING-BACKUP-5.278 ID X .076-#8-355
1
490
40147
GASKET, 2B A
1

17
CROSS SECTIONAL ASSEMBLY DRAWING

18
EXPLODED ASSEMBLY DRAWING

19
INSTALLATION DRAWING
TWG
PO Box 1130
Jenks OK 74037-1130 USA
Phone:
918-298-8300
www.dovertwg.com