TM 5-4210-233-14&P-2
6-72. PLANETARY SPEED REDUCER-Continued
(10)
Before installing clamp nut (12), make certain lock screw is loosened. With thrust side of clamp nut
(12) down (side opposite stamped part number), insert between posts of secondary carrier (9).
Carefully place carrier over threaded end of output shaft (13), making sure not to damage threads
on shaft. Move carrier by hand until you are certain carrier spline has started cleanly and squarely
onto shaft spline. Press carrier slowly onto shaft spline. Be sure hub on secondary carrier (9)
slides through seal lip (14A) without damaging ft. Rotating case (14) while carrier hub starts through
seal will help. Continue slowly pressing carrier on shaft until you feel slight increase in drag load as
you are rotating case. At this point, bearings are seated and it's time to set bearing preload.
Proper bearing preload will be determined by rolling torque method. This method involves
increasing press load until drag or rolling resistance of 50 to 80 in Ibs (6 to 9 Nm) torque is
achieved when rotating case, including seal drag. This torque is equal to a force of 11 to 18 Ibs (5
to 8 kg) when rotating case (14) by pulling on one of support ribs that are located above mounting
flange. If uncertain, use a fish scale or similar measuring devise to check rolling torque.
CAUTION
If lock screw in side of clamp nut (12) is not accessible to hex
wrench, loosen clamp nut to first accessible location for
tightening. DO NOT tighten nut to obtain lock screw access. If
nut is tightened too much before lock screw is tightened, nut will
spread apart and touch only one side of shaft threads. This
would allow nut to unscrew if highly loaded. Clamp nut threads
need to contact both sides of shaft threads to be properly locked
into position.
(11)
Once proper bearing preload is achieved, start threading clamp nut (12) onto output shaft (13)
while maintaining press load. Tighten nut all the way down to carrier spline until "hand tight."
Using a 5 mm hex wrench, torque lock screw in clamp nut to 150 in Ibs (17 Nm). This will securely
clamp nut to output shaft threads. Press load may now be relieved.
(12)
Lubricate O-ring (11) with oil (Item 45, Appendix E) and place over pilot on case (14).
WARNING
Hold ring gear by outside diameter to avoid injuring fingers or
sharp gear teeth.
(13)
With dowel holes pointing down, place ring gear (8) over secondary carrier assembly. Rotate ring
gear (8) back and forth to line up planet gear teeth (30A) with ring gear teeth (8). While letting ring
gear down to case, rotate until dowel pins (10) line up with dowel holes. Orient one of two drain
holes in ring gear as near as possible to grease fitting in case.
(14)
Place heavy plate over ring gear (8) and press down, leaving 1/4" gap between ring gear and case
(14). To be sure ring gear orientation is correct, start eight case bolts (7A) with lockwashers (7B)
into ring gear. if bolt holes are not properly aligned it will be easier to remove ring gear with 1/4"
gap left. If bolt holes line up, press ring gear (8) down tight against case.
(15)
Tighten eight case bolts (7A) to 32 ft Ibs (43 Nm).
(16)
Put pipe sealant (Item 2, Appendix E) on two drain plugs (2) and install into drain holes in ring gear
(8).
6-425
