GMC 1989 Light Duty Truck, Руководство по ремонту, Страница: 941 / 998

TRANSFER CASE 7D1-1
SECTION 7D
TRANSFER CASE
CONTENTS
SUBJECT PAGE
New Process 205 Transfer C a s e ................................................................................................................................................ 7D1-1
New Process 241 Transfer C a s e ................................................................................................................................................ 7D2-1
New Process 231 Transfer C a s e ................................................................................................................................................ 7D3-1
Borg Warner 1370 Transfer C a s e ................................................................................................................................................ 7D4-1
SECTION 7D1
NEW PROCESS 205 TRANSFER CASE
CONTENTS
SUBJECT PAGE
D escription................................................................................................................................................................................7 D 1 - 1
Disassem bly..................................................................................................................................................................................7 D 1 - 2
Rear Output Shaft and Yoke A ssem b ly........................................................................................................................... 7 D 1 - 2
Front Output Shaft A ssem bly............................................................................................................................................. 7 D 1 - 2
Shift Rail and Fork A s s e m b lie s .........................................................................................................................................7 D 1 -
3
Idler G e a r ..................................................................................................................................................................................7 D 1 -
3
M iscellaneous........................................................................................................................................................................... 7 D 1 -
3
Cleaning and In spectio n ........................................................................................................................................................... 7 D 1 - 7
A s s e m b ly ...................................................................................................................................................................................... 7 D 1 - 7
Idler G e a r ..................................................................................................................................................................................7 D 1 - 8
Shift Rail and Fork A s s e m b lie s .........................................................................................................................................7 D 1 - 8
Front Output Shaft A ssem bly............................................................................................................................................. 7 D 1 - 8
Rear Output Shaft A s s e m b ly ............................................................................................................................................. 7 D 1 - 9
Miscellaneous...........................................................................................................................................................................7 D 1 -1 0
S p e c ific a tio n s ............................................................................................................................................................................. 7D 1-11
Special T o o ls ............................................................................................................................................................................... 7D1 -11
DESCRIPTION
A transfer case mounts behind the transmission and
allows drive torque to be transmitted in a proportional split
to both the front axle and the rear axle, resulting in
four-wheel drive. The shift control lever for the transfer
case is floor-mounted in the passenger compartment.
Depending on the type of transfer case and the shift lever
position, various combinations of rear wheel drive, four
wheel drive, high traction (gear reduction) or direct drive
may be selected.
The model 205 transfer case is a two-speed unit which
can be used for either two-wheel or four-wheel drive.
Direct drive (1:1 ratio) is available in two modes, 2H for
two-wheel drive, or 4H for four-wheel drive. Gear
reduction (1.96:1 ratio) is used in the 4L position. This unit
uses constant mesh helical gears to connect the input
shaft, idler gear and two out put gears, thus allowing gear
selection to match driving conditions. The front input shaft
gear is in constant mesh with the idler gear and, through
the idler gear, with the front output gears and the rear
output gear. Sliding clutches allow for selective gear
engagement resulting in High or Lo range, and two-wheel
or four-wheel drive. Ball bearings support the input shaft,
rear output shaft and front output shaft. Tapered roller
bearings are used on the idler shaft. When driving in a
four-wheel mode (4L or 4H) the hubs on the front wheels
must be turned to the “ Locked” position.
IDENTIFICATION
An identification tag is attached to the power take-off
cover transfer case. This tag provides the transfer case
model number, low range reduction ratio, and assembly
number. The information on this tag is necessary for servic­
ing information. If the tag is removed or becomes dislodged
during service operations it should be reattached.