PRM NEWAGE PRM 60 Instruction manual

PRM 60
WORKSHOP
MANUAL

1
PRM NEWAGE LIMITED
BARLOW ROAD
COVENTRY
CV2 2LD
ENGLAND
TELEPHONE: [phone]
EMAIL: [e-mail]
WEBSITE: www.prm-newage.com
PRM 60 Manual
Issue: 1.6
Created By: E. MIDDLETON
N. GEORGIEV
Update: December 2020
PRM Newage Ltd operates a policy of product improvement and therefore reserves the right to
change specifications without prior notification. Whilst every effort is made to ensure complete
accuracy of the information in this manual no liabilities for inaccuracies or the consequences thereof
can be accepted by the manufacturer or the distributor who supplied the manual.
This manual contains proprietary information of PRM Newage Limited. It is intended solely for the
information and use of parties operating and maintaining the equipment described herein. Such
proprietary information may not be used, reproduced, or disclosed to any other parties for any other
purpose without the express written permission of PRM Newage Limited
The following international symbols are used in this service manual:
WARNING! THIS SYMBOL WARNS OF POSSIBLE PERSONAL INJURY
CAUTION! THIS SYMBOL WARNS OF POSSIBLE DAMAGE TO TRANSMISSION

2 -PRM 60
CONTENTS
LIST OF ILLUSTRATIONS 3
FOREWORD 4
CLAIMS UNDER WARRANTY 4
SERVICE PARTS 4
PRE-DELIVERY TEST 4
IDENTIFICATION PLATE INFORMATION 5
SERVICE CLASSIFICATION DEFINITIONS 6
1. GENERAL DATA 6
1.1 Specifications 6
2. INTRODUCTION 7
3. CONSTRUCTION 7
3.1 Gearcase 7
3.2 Gear train 7
4. OPERATION 7
4.1 Output Rotations 7
4.2 Lubrication 7
4.3 Approved oils and oil filling 7
5. INSTALLATION 8
5.1 General 8
5.2 Checking the Engine Flywheel Housing 8
5.3 Checking the Engine Flywheel 8
5.4 Mounting the Gearbox to the Engine 10
5.5 Alignment to Propeller Shaft 10
5.6 Installation angle 11
5.7 Remote control operating systems 12
6. OPERATION 13
6.1 First time usage 13
6.2 Drive selection 13
6.3 Trailing (free wheeling) the Propeller 13
7. ROUTINE MAINTENANCE 14
7.1 Initial maintenance (after 25 hours running) 14
7.2 Daily checks 14
7.3 Six monthly check 14
7.4 Annual check 14
7.5 Cone Clutch Adjustment 14

3 -PRM 60
8. FAULT FINDING 15
9. SERVICING AND REPAIRS –GENERAL 16
9.1 Seals 16
9.2 Bearings 16
9.3 Cleaning 16
9.4 Inspection 16
9.4.1 Gearcase 16
9.4.2 Gears 16
9.4.3 Bearings 16
9.4.4 Threaded parts 16
9.5 Assembly 16
9.6 Disassembly of Gearbox 16
9.6.1 Selector assembly 16
9.6.2 Gearcase assembly 17
9.6.3 Input Shaft 17
9.6.4 Output Shaft 17
9.6.5 Idler Shaft 17
9.6.6 Selector 17
9.6.7 Front Cover 17
9.6.8 Gearcase 17
9.7 Re-assembly of Gearbox 17
9.7.1 Input shaft 17
9.7.2 Output shaft (see 9.7.5 for Shimming procedure) 17
9.7.3 Idler Shaft 18
9.7.4 Selector Housing assembly 18
9.7.5 Shimming (Output Bearings ) 18
9.7.6 Cone Clutch Selection 19
10. SPECIAL TOOLS 19
10.1 Tool Kit 19
10.2 Tightening torques 19
11. REPLACEMENT PARTS ORDERING 19
12.PARTS LIST 20
* USE LOCTITE THREAD SEALANT 542 ON THREAD 20
13. EXPLODED VIEW AND CROSS- SECTION 21
SPARES KITS 25
LIST OF ILLUSTRATIONS
Figure 1 - Example of Serial Plate 5
Figure 2 - Blank Serial Plate 5
Figure 3 - Checking the Flywheel and Flywheel Housing 8
Figure 4 –Intallation Details 9
Figure 5 - Exploded view and cross-section 21

4 -PRM 60
FOREWORD
Provided it is correctly installed, aligned and maintained, the PRM 60 gearbox should have a long and trouble-free life.
This workshop manual contains important instructions to ensure that this is so, and it is of the utmost importance that
these are carefully followed. PRM Newage Ltd. can accept no responsibility under warranty or otherwise for any loss or
damage resulting from failure to observe these instructions.
To avoid prejudicing your rights under warranty, do not undertake any repair or other work on the gearbox during the
warranty period without first contacting PRM Newage Ltd. or an authorised distributor/dealer for advice. In the event of
failure, you should do this via the engine distributor who supplied the gearbox, or his local dealer; if this is not possible,
you should notify the local PRM Newage distributor/dealer or PRM Newage Ltd. direct, quoting the serial number.
CLAIMS UNDER WARRANTY
Claims for replacement of parts under warranty must always be submitted with the gearbox serial number to the
distributor who supplied the gearbox; if this is not possible, application may be made to the nearest distributor, who
must, however, be advised of the supplier's name and address.
SERVICE PARTS
The comprehensive illustrated parts list gives full information and ordering procedure.
PRE-DELIVERY TEST
Before it leaves the factory, every gearbox is subjected to a final test and inspection which includes the following: -
1. Flush clean.
2. Pressurise the case, and check for oil leaks.
3. Check drag torque in ahead, neutral and astern.
4. Run the gearbox in neutral, ahead and astern in load conditions.
5. Check force to engage and disengage ahead and astern gear.
6. Check noise levels.
7. Check output nut torque.
8. Check coupling concentricity.
IMPORTANT NOTICE: ONLY REMOVE BREATHER, DIP
STICK, OIL DRAIN PLUG OR OIL LEVEL PLUG ONCE
THE GEARBOX IS AT AMBIENT TEMPERATURE.
REMEMBER HOT OIL CAN CAUSE BURNS –WORK
SAFELY.

5 -PRM 60
IDENTIFICATION PLATE INFORMATION
Every PRM gearbox is fitted with an identification plate on the top half of the gearcase before it leaves the factory;
an example of such a plate is shown below.
Please complete the above box with serial number and specification of your own gearbox.
It will be noted that there are two lines of numbers.
The top line is the gearbox serial number, and should always be quoted when ordering spare parts; the lower line is the
gearbox specification, in the example given this translates as follows:-
60 D 2
First 2 digits –Gearbox Model (60)
Third digit –Output Shaft configuration
Fourth/fifth digit –Ratio
NOTE: Throughout this manual, engine, gearbox and propeller rotation are always described as seen looking
forward from the propeller to the engine.
SERIAL NUMBER
WORKS ORDER NUMBER
GEARBOX
MODEL
OUTPUT SHAFT
CONFIGURATION
VXXXXX
WXXXXX
D
60
2
RATIO
Figure 1 - Example of Serial Plate
Figure 2 - Blank Serial Plate

6 -PRM 60
SERVICE CLASSIFICATION DEFINITIONS
PLEASURE Limited to craft used exclusively for pleasure boating; operation at full engine throttle should not
exceed 5% of total time, with balance of usage at 90% of full throttle engine speed, or less. Maximum operation 500
hours per year. The selection of PRM 60 according to this classification for any commercial boat is not approved by
PRM Newage Limited.
LIGHT COMMERCIAL PRM Newage Limited recommends that when considering the use of the PRM 60 in boats
of whatever hull form used in light commercial applications, and in displacement and semi-displacement hull boats for
pleasure applications, these boats should be classed as light commercial duty and the gearbox selected accordingly.
Maximum operation –2000 hours per year.
IMPORTANT NOTE: It is essential for the engine, transmission model, reduction ratio and propeller size to be
correctly matched so that the engine can attain its rated speed appropriate to the relevant service classification
without labouring.
1. GENERAL DATA
1.1Specifications
Gear ratios –ahead
1.52:1 2.00:1 2.50:1
Gear ratio –astern
2.05:1 –common
POWER RATING
MODEL
AHEAD RATIO
PLEASURE
LIGHT COMMERCIAL
BHP
kW
BHP
kW
60D1.5
1.52:1
0.98
0.73
0.80
0.60
60D2
2.00:1
0.85
0.63
0.68
0.51
60D2.5
2.50:1
0.85
0.63
0.58
0.43
Max. Input Power
35
26
28
21
NOTE: These powers are expressed in BHP and kW per rev/min engine speed, and are measured at the engine
flywheel. Ratings have been established to ensure the long trouble-free life of the gearbox which should not,
therefore be used at powers in excess of those shown.
Input speed:
Maximum operating speed 5000 rev/min.
Input rotation:
For engines of left-hand (anti-clockwise) rotation as viewed looking on the flywheel from behind the engine.
Output rotation:
Right-hand (clockwise) in ahead direction. IMPORTANT: RIGHT HAND PROPELLER REQUIRED.
Approximate dry weight:
10 kg (22lbs) excluding adaptor flange.
Oil capacity:
Approximately: 0.20 litres (0.35 pints)
Working oil temperature:
The normal operating temperature should be in the range 50°C to 95°C continuous.
Engine Mounting Adaptors:
Available in SAE5 and Velvet Drive (Borg Warner).
Input Drive Couplings:
Flexible centre damper plate SAE 6.5” or SAE 7.5”.

7 -PRM 60
Input Shaft:
28.5mm diameter with 10 tooth spline to DIN5464.
Propeller thrust:
Ahead and astern thrust is carried by output shaft bearings of ample capacity for the approved rating.
Output flange:
102mm diameter, with 4 holes 10.5mm diameter on 82.5 pitch circle diameter.
Installation angle:
The maximum fore and aft installation angle at rest is 15°.
2. INTRODUCTION
Prior to installation of the PRM 60 read and follow the instructions within this manual. Failure to do so will make the
warranty void. PRM will not be responsible for poor installation, wrong handling or defficient maintainence. It is the
responsibility of users to install guards and safety devices within maybe required by Health and Safety directives within
different countries.
The PRM 60 marine transmission is a simple, lightweight, mechanically operated gearbox for use in pleasure craft.
Ahead and astern is selected by engaging a cone clutch which requires no adjustment. The PRM 60 can only be
installed onto engines that rotate left hand (anti-clockwise) as viewed when standing behind the gearbox output
coupling facing towards the engine flywheel.
3. CONSTRUCTION
3.1 Gearcase
The gearcase is made from heavy duty aluminium alloy rigidly designed and externally ribbed for efficient heat
dissipation. The case assembly comprises two halves vertically split to facilitate servicing.
3.2 Gear train
The helical gear train is manufactured from high grade steel with all gears being case hardened for long life. All shafts
are supported on ball bearings which are amply proportioned to absorb all the thrust from the propeller.
4. OPERATION
4.1 Output Rotations
With the control lever in the mid, or neutral position no power is transmitted to the propeller as the cone clutch is not
engaged with either ahead or astern gears. Moving the lever forward i.e. towards the engine selects ahead, and
rearwards i.e. towards the propeller selects astern. In ahead the output shaft rotates in the opposite direction to the
input shaft (which rotates as engine). It is therefore necessary to fit a right hand propeller.
4.2 Lubrication
All lubrication is supplied by internal splash with oil cooling being by radiation through the gearbox case.
4.3 Approved oils and oil filling
The gearbox is supplied direct to the distributor/ coustomer without oil and therefore prior to start up it must be filled with
oil. Unscrew the oil level plug located on the side of the gearbox. Unscrew the oil filling plug located on the top of the
gearbox. Fill the gearbox with ATF DEXTRON II, III, or IV to GM specification or engineering approved equvalent until
oil starts draining from the level hole. Refit the oil level plug. Check the oil on the dipstick. Refit the oil filling plug. The oil
is approximately 0.2 litres.
CAUTION: Do not mix different brands, types or grade of oil.
DO NOT OVERFILL THE GEARBOX AS THIS AFFECTS THE GEARBOX PERFORMENCE.

8 -PRM 60
5. INSTALLATION
5.1 General
Drive is transmitted from the engine to the gearbox via a flexible centre drive plate (damper plate) which bolts to the
engine flywheel, the gearbox input shaft is driven from the centre spline.
These drive plates have a degree of torsional flexibility, the purpose being to reduce engine torsional or cyclic vibrations
and prevent them being passed to the transmission.
The strongest engine vibrations are usually those caused by firing in the cylinders; diesel engines which have high
compression ratios, usually generate stronger vibration pulses than petrol (gasoline) engines; and it is often the case
that of two engines of roughly equivalent size, the one having the greater number of cylinders will tend to run more
smoothly than the one with fewer cylinders, although this is by no means always the case.
In all marine installations, correct alignment of the engine, gearbox and propeller shaft is extremely important –
misalignment can cause noise, vibration and premature failure –and it is strongly recommended that all the procedures
detailed in this manual are carefully followed.
CAUTION: It is particularly important to ensure the torsional compatibility of the complete
propulsion system from engine through to propeller since disregarding this may result in gear
noise at low speed operation and in extreme cases damage or failure of components. PRM Newage
Ltd. will provide all possible information and assistance to help find solutions to potential torsional
problems, but it is the ultimate responsibility of the person assembling the drive and driven
equipment to ensure that they are torsionally compatible.
5.2 Checking the Engine Flywheel Housing
Attach a dial test indicator, calibrated in units of 0.025mm (0.001in.) or smaller, to the flywheel so that the measuring
stylus of the indicator is perpendicular to the bore of the flywheel housing (bore A on Fig.2). Rotate the flywheel and
check the deviation on the indicator over one complete revolution; this should not exceed 0.152mm (0.006in.) total
indicator reading.
With the dial test indicator still attached to the flywheel, re-position the stylus so that it is perpendicular to the face of the
flywheel housing (face B on Fig. 2), Rotate the flywheel and check the deviation over one complete revolution; again,
this should not exceed 0.152mm (0.006in.) total indicator reading.
5.3 Checking the Engine Flywheel
Attach a dial test indicator, calibrated to 0.025mm (0.001in.) or less, to the engine flywheel housing so that the
measuring stylus of the indicator is perpendicular to the bore of the register in the flywheel (bore C on Fig. 3). Rotate the
flywheel through one complete revolution and note the deviation, this should not exceed 0.125mm (0.005in.) total
indicator reading.
With the dial test indicator still attached to the flywheel housing, reposition the stylus so that it is perpendicular to the
face of the flywheel register (D on Fig. 3). Rotate the flywheel through one complete revolution and note the deviation,
this should not exceed 0.125mm (0.005in.) total indicator reading.
Figure 3 - Checking the Flywheel and Flywheel Housing

9 -PRM 60
BASIC INSTALLATION DETAILS –PRM 60
Figure 4 –Intallation Details

10 -PRM 60
5.4 Mounting the Gearbox to the Engine
1. Mount the drive plate to the flywheel, using an alignment mandrel if available, and bolt to the flywheel. Where
components to SAE standard are used, the outside diameter of the drive plate should be a close fit in the register
on the flywheel.
If a mandrel is not available, tighten the bolts just sufficiently to prevent free movement, assemble the gearbox to
the drive plate and rotate the engine two or three revolutions by hand to align the plate.
Tighten up two or three opposite bolts. Remove the gearbox and fully tighten all the drive plate bolts.
2. Apply a layer of water-repellent grease to the input shaft spline and then offer the gearbox and adaptor up to the
drive plate and flywheel housing. Insert the gearbox input shaft into the centre of the drive plate (it may be
necessary to rock the shaft slightly to ensure the splines align). Press the assembly fully into position, align the
holes in the adaptor with those on the flywheel housing and tighten fully. See fastening torque chart 10.2.
5.5 Alignment to Propeller Shaft
CAUTION: Alignment between the propeller shaft and the mating flange on the gearbox output
shaft is extremely important since excessive vibration and stress may lead to premature failure if
correct alignment is not achieved.
In the majority of boats whose hulls are rigid enough to prevent excessive flexing in heavy sea conditions, (which could
cause the engine and transmission to shift relative to the propeller shaft), it is generally considered preferable to couple
the propeller shaft direct to the gearbox output flange by means of a rigid coupling.
The two main conditions when a flexible coupling should be used are:
a) in boats whose hulls are not sufficiently rigid to prevent the flexing referred to above,
b) in cases where the engine is mounted on flexible mounts.
In both instances, the flexible coupling helps to isolate engine vibration or other movement from the propeller shaft thus
enabling correct alignment with the propeller shaft and stern tube to be maintained.
Whether a solid or flexible coupling is used, it is extremely important that the following points are carefully checked:

11 -PRM 60
i) the coupling should be a tight press fit on the shaft and the keyway accurately made to the correct size, and
ii) the two halves of the coupling should be carefully aligned. This should be done by bringing the two flanges close
enough together so that a feeler gauge can be used to check the vertical and horizontal alignment.
iii) alignment should only be carried out with the boat afloat. The maximum permissable misalignment being 0.05mm.
Since the propeller shaft line is normally fixed in the boat, alignment is usually obtained by adjusting engine mount
shims on the mount themselves.
NOTE: Whenever possible, the engine and gearbox should be installed whilst the hull is afloat, otherwise there is a
danger of the hull distorting because of an insufficient support over its surface. If the engine and transmission are fitted
before the hull is in water, the installation should be very carefully re-checked for alignment after launching.
In designing PRM 60, SAE standards were adhered to as far as possible. However, other manufacturers of similar sized
transmissions have a different, but common, output coupling spigot, which is not to SAE. This spigot size has become
the industry standard and most proprietary flexible output couplings are made to suit.
5.6 Installation angle
The transmissions should normally be installed so that the maximum fore and aft angle relative to the water line does
not exceed 15° with the boat at rest. Please consult PRM Newage Ltd. if installlation angles greater than this are
required.

12 -PRM 60
5.7 Remote control operating systems
The engine must be at idle before changing direction, therefore the PRM 60 should be used with remote control
operating systems which must be of the single lever type of remote control, i.e. Morse MT3 or SL3 which controls both
the engine throttle and gear selection. The stroke of the lever between forward and reverse selection must not be less
than 60mm lower hole and 70mm upper hole. Make sure the lever forward position corresponds to the forward
movement of the vessel.
The following points should be noted:
i) The gearbox operating lever is provided with a positive neutral position, which greatly assists the setting up of the
remote control unit.
ii) CAUTION: CARE SHOULD BE TAKEN TO ENSURE THAT THE FLEXIBLE CABLE IS CAPABLE
AND CAN MOVE THE FEARBOX LEVER FREELY TO THE FULL EXTENT OF ITS TRAVEL BOTH
FORWARD AND BACKWARD AND THAT ITS NEUTRAL POSITION IS CORRECT FOR THIS TO TAKE
PLACE.
The control equipment should in all cases be connected in accordance with the manufacturer’s recommendations.

13 -PRM 60
6. OPERATION
6.1 First time usage
CAUTION: Before starting the engine fill the gearbox to the correct level with a suitable oil (refer to
recommended list, section 4.3).
Ensure the gearbox is in neutral. Start and run the engine for a short time so that the oil circulates through the gearbox.
Stop the engine and allow the oil to settle for two minutes, re-check the level and top up to the marked oil level.
NOTE: The dipstick should be secured firmly when checking the oil level.
6.2 Drive selection
The PRM 60 has been designed to operate with proprietary single lever control systems which decreases the engine
speed to idle before opposite gear selection can be made. It is most important that when changing direction a short
pause is taken in neutral at engine idle before selecting gear. (see section 5.7)
6.3 Trailing (free wheeling) the Propeller
The output shaft can be rotated in neutral continually with the engine shut down which makes the PRM 60 particularly
suited for use in auxiliary sailboats, sailing yachts etc. Never put the lever in the position corresponding to the direction
of the vessel.

14 -PRM 60
7. ROUTINE MAINTENANCE
7.1 Initial maintenance (after 25 hours running)
Drain all oil from the gearbox, the drain plug is located on the side of the transmission, below the selector lever.
Refit drain plug. Refill with oil as stated in 4.3.
7.2 Daily checks
Check the gearbox oil level on dipstick.
Visually inspect for oil leaks and general condition of the gearbox.
7.3 Six monthly check
Check the remote control operating linkage is accurately adjusted to give maximum travel (stop to stop) in both
directions.
7.4 Annual check
All above checks.
Propeller shaft alignment inspection.
Change gearbox oil and after 500 hours or annually which ever comes first.
7.5 Cone Clutch Adjustment
The cone clutch is self-adjusting and therefore needs no adjustment. Should gear selection become difficult it is
advisable to check the installation and operaion of the control cable as discribed in 5.7. if this is correct then the cone
clutch adjustment can be carried out as decribed in 9.7.6. if problems persist after the adjustment, it will be necessary to
dissassemble the gearbox to investigate the condition of the cone clutch.
If the cone clutch shows signs of loss of coating, glazing and heat discoloration and the mating gears shows signs of
heavy groove indentations then the cone clutch and the mating gears must be replaced. If only the gears are replaced
then the adjustment of the cone clutch is not required. If the cone clutch is replaced then adjustment needs to be carried
out as described in 9.7.6.

15 -PRM 60
8. FAULT FINDING
The following fault finding chart is designed to help diagnose some of the problems which might be encountered. It
assumes that the installation and operating instructions in this manual have been followed and we advise that these are
checked before proceeding to fault finding.
To avoid prejudicing warranty rights, no repair or other work should be done on the gearbox during the warranty without
first contacting PRM Newage Ltd. or an authorised distributor or dealer for advice.
FAULT FINDING CHART
SYMPTOM
CAUSE
REASON
REMEDY
No drive ahead or astern
Broken drive plate
Broken input shaft
Broken output shaft
Replace drive plate
Replace input shaft
Replace output shaft
Propeller speed does not
increase with engine speed,
ahead and astern
Remote control cable or
linkage not allowing F-N-R
lever to move correct
distance
Too much oil within gearbox
Remove cable and operate lever
by hand to check movement.
Adjust cable if necessary
Recheck oil level and adjust.
Propeller speed does not
increase with engine speed
in one direction only
Damaged clutch cones
Incorrect lever setting
Too much oil within gearbox
Remove and examine clutch
and replace if necessary
Reset lever to end stops
Recheck oil level and adjust.
Excessive noise from
gearbox at low speeds
Engine idle speed set too low
Torsional vibration
Faulty adjustment
Torsional incompatibility of
elements in driveline
Increase idling speed
If not cured by increasing engine
idling speed, refer to engine
supplier
Excessive noise throughout
operating range
Defective input coupling
Propeller shaft misalignment
Input coupling worn or
damaged
Hull flexing or faulty
installation
Remove, examine and replace if
necessary
Check the alignment of the
propeller shaft coupling; if
necessary rectify by adjusting
the shims under the engine
mounts or the engine mounts
themselves
Excessive vibration
throughout operating range
Propeller out of balance
Engine/gearbox
misalignment
Defective bearing
Propeller damaged or badly
machined
Faulty installation
Bearing worn or damaged
Remove the propeller and check
that the pitch, weight, diameter
and balance of all the blades are
equal and rectify if necessary
Remove the transmission and
check that the flywheel face is
flat and that the flexible input
coupling is aligned correctly
Isolate defective bearing,
remove and replace
Excessive oil temperature
Power too high
Oil level too high/low
Incorrect engine rating
Incorrect oil type
Re-assess engine power
Fill with correct oil
Fill to correct oil level on dipstick
Oil level needs constant
topping up
Oil leaks
Defective oil seal, sealant or
‘O’ ring
Clean the outside of the
gearcase, particularly around
the ends of shafts including the
output shaft. Run the engine
and inspect the gearbox for
leaks. Replace seals as required
Escape of high pressure from
gearbox when dipstick is
removed
Defective breather causing
leaks past oil seals
Contact distributor or factory for
advice
Difficulty in moving single
lever control
Faulty installation
Incorrect selector adjustment
Remote control operating
cable kinked or frayed
Re check adjustment see 9.7.6
for procedure
Check the installation and
eliminate all tight bends in the
cable
Warning: Before carrying out any service work always ensure that the engine is switched off and
disconnect the operating cable from the gearbox.
Caution: The above operations should be carried out by suitably qualified personnel and strictly in
accordance with the procedures detailed in the workshop manual

16 -PRM 60
9. SERVICING AND REPAIRS –GENERAL
WARNING: Before removal of the gearbox for repair or overhaul carefully study the following
procedures. Use proper hand tools, slings or hoists for the job –WORK SAFELY
Keep all work areas, tools and gearbox clean. Wipe up and spilled oil or fluids to prevent accidents.
Wear correct safety equipment i.e. safety glasses and safety shoes to guard against personal injury/
Remember WORK SAFELY –USE COMMON SENSE.
Drawings showing all internal components are contained in the parts list.
9.1 Seals
Remove oil seals carefully to prevent damage if they are to be re-used, however it is best to replace these items.
9.2 Bearings
If removing bearings for re-use keep them in a clean area to prevent dirt contamination.
9.3 Cleaning
WARNING: If using cleaning solvents these can be toxic, flammable, a skin irritant or give off harmful
fumes. Avoid prolonged contact, vapour inhalation, or smoking. Failure to take care can result in injury
or death.
Rinse all metal parts in solvent to remove dirt, grease and oil.
Be careful to remove solvent from items before re-fitting.
9.4 Inspection
9.4.1 Gearcase
Inspect for cracks. Check sealing surfaces for any scratches, damage etc. which will lead to oil leaks.
9.4.2 Gears
Inspect for any chipped broken or cracked gear teeth, also for any excessive wear, i.e. gear pitting.
9.4.3 Bearings
Inspect for any damage, pitting or over-heating.
9.4.4 Threaded parts
Inspect for stripped or damaged threads.
9.5 Assembly
CAUTION: All threaded fasteners must be tightened to the torques listed in table 10.2, to prevent
premature failure.
CAUTION: A new drive flange nut must be fitted if this is removed. Prior to assembly oil all internal
parts with clean gearbox oil.
9.6 Disassembly of Gearbox
Drain oil and remove adaptor plate. Hold output coupling (23) securely whilst removing locknut (36) , carefully remove
the “staked” portion of locking device so as to avoid damaging the thread of the output shaft (14).
9.6.1 Selector assembly
Remove the output coupling (23). Remove the two socked head cap screws (42) securing selector housing (19).
Withdraw selector assembly ensuring selector shoe (22) and spring (15) do not fall into the gearbox.

17 -PRM 60
9.6.2 Gearcase assembly
Remove the external locknut (25) securing idler shaft (7) into gearcase (2). Remove the ten bolts (56) securing both
gearcases (1, 2) and using a soft mallet lightly tap on the end of the input shaft (3) to separate the two gearcase (1, 2)
halves from sealant and dowels (27). Remove the front cover (1). Withdraw the idler shaft (7) the output shaft assembly
and the input shaft (3).
9.6.3 Input Shaft
Removal of the bearings (34, 38) may damage them, therefore it is good practice to replace these items if removed.
(see 9.4.3)
9.6.4 Output Shaft
Carefully remove “staked” portion of locking device so as to avoid damaging the thread and remove locknut (13) from
output shaft (14). Using a bearing puller remove the bearing (33) on the output end of the shaft (14).
Remove the following: thrust washer (8), forward output gear (10) , needle bearing (37) (carefully checking for wear),
thrust washer (9) , cone clutch (11). Using puller remove the bearing (33) on the input end of the shaft (14), thrust
washer (8), output revese gear (12), needle bearing (37) (again carefully checking for wear), and thrust washer (9).
Save shims for rebuild.
Note: Removal of ball bearings may result in damage, therefore replacement will be necessary.
9.6.5 Idler Shaft
Remove locknut (25) and supporting gear (6) on soft material i.e. wood or similar to prevent damage to gear (6), using a
soft mallet tap the shaft (7) through the gear (6) and remove needle bearing (4). Check condition of ‘O’ ring (55) on the
idler shaft (7).
9.6.6 Selector
By hand remove selector shoe (22) and the spring (15). Remove the lever (44). Pass the selector control body (18)
through the housing (19) and remove ‘O’ ring (20) and oil seal (21) if replacing them.
9.6.7 Front Cover
If it is required to replace the front cover (1) then it will be necessary to remove the oil seal (24). If the bearings (38, 33)
are to be re-used then care must be taken not to damage them on removal. It is recommended to fit a new oil seal (24).
Note: When re-fitting oil seal (24) set in 1.5mm from face as shown on page 18.
9.6.8 Gearcase
If it is required to replace the gearcase (2) then again if the bearings (33, 34) are to be re-used care must be taken in
their removal. Remove output seal (40), two studs (53), dipstick (28), drain and oil level plugs (26) with bonded washers
(31), oil filling plug (48) with bonded washer (54), and two dowels (27).
9.7 Re-assembly of Gearbox
(Note: coat all bearings with clean gearbox oil prior to fitting).
9.7.1 Input Shaft
Press the two bearings (38, 34) onto the input shaft (3) taking care to position correctly as illustrated. Make sure the
waved washer (39) is correctly positioned into case before fitting the input shaft (3).
9.7.2 Output Shaft (see 9.7.5 for Shimming procedure)
All of the following components are fitted in order over the output spline end of the shaft (14).
Thrust washer (9), needle bearing (37), output forward gear (10) with cone towards the scroll, thrust washer (8) and the
bearing (33) (Press on).
Fit the following components from the opposite end of the shaft (14).
The cone clutch (11), thrust washer (9), needle bearing (37), output reverse gear (12) , thrust washer (8), press on
bearing(33) (re-shim if components have been changed) (see 9.7.5). Fit lockwasher (35) and locknut (13).
CAUTION: Remember to tighten locknuts to recommended torque.
(SEE TORQUE CHART 10.2)

18 -PRM 60
9.7.3 Idler Shaft
Fit the thrust washer (5) onto the idler shaft (7), fit the two needle bearings (4) onto the idler shaft (7), fit the idler gear
(6) onto the needle bearings (4), then fit the ‘O’ ring (55) into the shaft’s (7) groove. Then apply grase on the the ‘O’ ring
(55). Feed the idler shaft assembly through the front cover (1) bore and fit the locknut (25) and tighten to the
recommended torque (see torque chart 10.2)
9.7.4 Selector Housing Assembly
* Before proceeding with this assembly see shimming procedure 9.7.6.
Press in oil seal (21) flush to the face of selector housing (19). Using tool number PR29418 insert into seal to expand it
whilst assembling selector control body (18) into the selector housing (19). This will displace the tool and allow the
control body (18) to slide through the seal (21). Fit the ‘O’ ring (20) to selector housing (19) and smear grease onto the
‘O’ ring (20), insert spring (15) and selector shoe (22) into selector housing (19).
9.7.5 Shimming (Output Bearings)
The output bearings (33) must be shimmed zero to 0.025mm preload.
This is achieved as follows:
1. Measure shaft (14) over the bearings (33). Dimension A
2. Measure gearcase (2) bore depth to joint face. Dimension C
3. Measure front cover (1) bore depth to joint face. Dimension B
4. Add cover and case bore depths to give “bore face lengths”. Dimension Y
5. Subtract bore face lengths from shaft (14) lengths over
bearings (33) to achieve shim requirement. Dimension Y-A
6. Fit shims as required to within zero to 0.025mm preload.
Place the shims into the appropriate bore of the front cover (1) so that they are located under the bearing (33).
Locate both input and idler shaft assemblies into the respective bores. Fit the two dowels (27) and apply silicon sealant
onto the joint face. Tighten the gearcase joint to the recommended torque (see torque chart 10.2).
Fit locknut (25) to the idler shaft (7), tighten to the recommended torque (see torque chart 10.2).
Move the cone clutch (11) to the neutral position, and locate the assembled selector mechanism and secure with two
cap screws (42) to recommended tightning torque (see torque chart 10.2). Ensure the selector shoe (22) is in the grove
of the cone clutch (11), and the identification pip of the selector shoe (22) is uppermost.
Secure gear selector lever (44) to the selector body (18) using bolt (45), washer (46) and nut (47). Fit oil seal (21) to
gearcase (2) bore and oil seal (24) to the front cover (1) (see tool sheet). Assemble the output coupling (23) to the
output shaft (14).
Apply a countiniues bead of silicone sealant to the flat face of the locknut (36) and hydraulic sealant to threads of the
shaft (14). Fit locknut (36).
CAUTION: Remember to tighten locknut (36) to the recommended torque and stake the nut into slot.
When using sealants and locking compounds all surfaces should first be cleaned by degreasing.