GMC S Series 1994, Repair Manual

Page: 893 / 919

SECTION 7D5
BORG-WARNER 4472 TRANSFER CASE
N O T IC E : W h e n f a s t e n e r s a r e r e m o v e d , a l w a y s r e in s t a l l t h e m a t th e s a m e lo c a t i o n f r o m w h ic h t h e y w e r e
r e m o v e d . I f a f a s t e n e r n e e d s to b e r e p la c e d , u s e t h e c o r r e c t p a r t n u m b e r f a s t e n e r f o r t h a t a p p lic a t io n . I f
t h e c o r r e c t p a r t n u m b e r f a s t e n e r i s n o t a v a ila b le , a f a s t e n e r o f e q u a l s iz e a n d s t r e n g t h ( o r s t r o n g e r ) m a y
b e u s e d . F a s t e n e r s t h a t a r e n o t r e u s e d , a n d t h o s e r e q u ir in g t h r e a d lo c k in g c o m p o u n d w il l b e c a l l e d o u t.
T h e c o r r e c t t o r q u e v a lu e m u s t b e u s e d w h e n in s t a llin g f a s t e n e r s t h a t r e q u i r e it. I f t h e a b o v e c o n d it io n s
a r e n o t f o llo w e d , p a r t s o r s y s t e m d a m a g e c o u ld r e s u lt.
CONTENTS
SUBJECT PAGE
General D escription..................................................................................................................................................... 7D5- 1
BW4472 Transfer Case.............................................................................................................................................7D5- 1
Identification........................................................................................................................................................... 7D5- 2
Power F lo w ............................................................................................................................................................. 7D5- 2
D isassem bly....................................................................................................................................................................7D5- 3
External Com ponents...............................................................................................................................................7D5- 3
Internal Com ponents................................................................................................................................................7D5- 3
Bearings and S e a ls .................................................................................................................................................. 7D5- 7
Cleaning and In sp ectio n .............................................................................................................................................7D5- 8
A ssem bly......................................................................................................................................................................... 7D5- 8
S p ecificatio n s................................................................................................................................................................ 7D5-12
Fastener Tightening Specifications......................................................................................................................7D5-12
Lubrication Specification........................................................................................................................................ 7D5-12
Special T o o ls ..................................................................................................................................................................7D5-12
GENERAL DESCRIPTION
B W 4472 TRANSFER CASE
The BW4472 is a three-piece aluminum, chain driven,
viscous clutch-type transfer case. This is used in a sys­
tem in which all-wheel drive is always activated. The
all-wheel drive is automatic and has no external controls.
The viscous clutch used in the BW4472 is a torque
distribution device and is nonserviceable. The internal
construction of the viscous clutch consists of alternating
plates that are connected to the front and rear outputs
of the transfer case. The clutch is filled with a high-vis-
cosity fluid which flows through slots in the plates. The
fluid’s resistance to sheering causes the plates to trans­
mit torque at the needed ratio to the front or rear
wheels. The ratio that torque is transmitted is approxi­
mately 35 percent front, 65 percent rear.