TM 5-2420-230-24-1
Spicer Speciality Axle Division - Technical Publications
SECTION 17
GEAR IDENTIFICATION ALSO CROWNWHEEL & PINION GEAR MESH.
Because we now produce gears by both Gleason and Oerlikon method of manufacture, the following
identification features are given to show differences between types of gears .
17.1 GLEASON GEARS
a)
Gear teeth taper towards centre (toe end of teeth).
b)
No suffix identification letter in part no. eg. R8579/1/2.
c)
No identification groove on pinion shank and crownwheel back face.
17.2 OERLIKON GEARS
a)
Gear teeth parallel to pitch line .
b)
Part no. has suffix identification letter 'N' eg.R8579/1N/2N.
c)
Pinion shank and crownwheel back face have identification groove.
NOTE :- The Oerlikon gears are cut in two forms :- N form and G form (Spiroflex)
At present, all gears except the following part nos. , are cut in N form.
gears cut in G form are as follows:-
R8939/1N/2N
R8858/1N/2N
R8859/1N/2N.
The only difference between the two forms is in mesh positions as shown in relevant
mesh checking diagrams in following section.
SECTION 18
CHECKING CROWNWHEEL AND PINION MESH.
18.1
Apply a thin coating of engineers marking compound to several consecutive crownwheel teeth.
18.2
Turn crownwheel for a few revolutions, in both directions to make a positive tooth contact impression
on crownwheel and pinion teeth.
18.3
Inspect deposit of marking compound on crownwheel and pinion teeth and compare them with
following relevant diagrams on pages C18 to C20
In all cases, action, (if any) to be taken is shown below:
Fig.A.
Indicates correct mesh.
No further action required.
Fig.B
Indicates pinion & crownwheel are too far out of mesh.
To remedy, move pinion inwards towards crownwheel.
To maintain backlash, move crownwheel away from pinion in
direction of arrow B
Fig. C
Indicates pinion & crownwheel too far into mesh.
To remedy, move pinion outwards away from crownwheel.
To maintain backlash,move crownwheel towards pinion in
direction of arrow B.
If any action is required, adjust pinion position by altering thickness of pinion bearing
shims (8A, B & C) ie.add shims to move pinion away from crownwheel and remove shims to move
pinion towards crownwheel.
18.4
When settings are correct, remove pinion bearing housing nuts with washers (5 & 6) then pull off pinion
assembly and lift off shims (8).
18.5
Thoroughly clean shims (8), also mating face of pinion housing and gear casing (7 & 12) using Loctite
Solvent no.7070 or other suitable chlorinated solvent.
18.6
Apply a thin film of Loctite no.515 liquid gasket to one side of each shim (8) then fit, Loctite side first,
onto studs (9).
18.7
Similarly coat pinion housing mating face (7) with Loctite no.515 liquid gasket and re-fit assembly to
gear casing (12), tapping into place with a hide faced hammer.
18.8
Secure in position with washer (6) and nuts (5). Tighten nuts progressively using diagonal selection,
until tightened to correct torque. 47 - 53 lbs. ft. (64 - 72 Nm).
Page No.C17
Manual No. 1785 Issue A
Spicer Speciality Axle Division
J-81
