Eaton TRSM0515, Service Manual

Page: 3 / 88

It is essential that the two countershafts are timed.
This assures that the countershaft gears will con-
tact the mating mainshaft gears at the same
instant, allowing the mainshaft gears to seek their
equilibrium position. This prohibits the mainshaft
gears from climbing out of position and prevents
unequal tooth contact.
Timing one set of gears, the drive gear set, is all
that is necessary. It is a simple procedure, consist-
ing of marking the proper teeth prior to installation
and meshing the teeth so marked.
A. Marking countershaft drive gear teeth.
1. Prior to placing each countershaft assem-
bly into case, clearly mark on each drive
gear the gear tooth which is directly over the
keyway in gear. (See illustration A.) This
tooth is stamped with an "O" to aid iden-
tification.
A. TOOTH ON
COUNTERSHAFT
DIRECTLY OVER
KEYWAY MARKED
FOR TIMING
B. Marking drive gear teeth.
1. Mark any two adjacent teeth on the drive
gear.
2. Mark the two adjacent teeth on the drive
gear which are directly opposite the first set
marked. There should be an equal number
of teeth between the markings on each side
of gear. (See Illustration B.)
B. DRIVE GEAR TEETH
Cut 7300A
CORRECTLY MARKED
FOR TIMING
C. Meshing marked countershaft gear
teeth with marked drive gear teeth.
(After installing drive gear and main-
shaft assemblies, the countershaft
bearings are installed to complete
countershaft installation.)
1. W h e n i n s t a l l i n g b e a r i n g s o n t h e l e f t
countershaft, mesh the marked counter-
shaft gear tooth between two marked teeth
on the drive gear. Repeat the procedure
when installing the right countershaft bear-
ings. (See Illustration C.)
C. COUNTERSHAFT GEAR TEETH
MESHED WITH DRIVE GEAR TEETH
FOR CORRECT TIMING
D. Timing auxiliary section.
(In the auxiliary section, the low speed gear set
is marked for timing instead of the drive gear
set.)
1.
2.
3.
4.
5.
6.
Mark any two adjacent teeth on the large
mainshaft low speed gear, then mark the
two adjacent teeth directly opposite„the
same procedure as used when marking the
front section drive gear.
On each auxiliary countershaft assembly,
mark the tooth on the small low speed gear
which is stamped with an "O".
Install the low speed gear and tailshaft
assembly in auxiliary housing.
Partially install outer races of countershaft
rear bearings in case bores.
Place the auxiliary countershaft assem-
semblies into position, meshing marked
tooth on each countershaft gear between
marked teeth on low speed gear. Counter-
shafts will be partially seated in rear bear-
ing.
Fully install rear bearings to complete aux-
iliary countershaft installation.
TIMIMG