New Venture Gear Model 231
The Model 231 will allow the driver to select between the following
ranges:
| • | 4-wheel drive high range |
| • | 4-wheel drive low range |
This model is a part-time four-wheel drive unit.
Torque input in four-wheel high and low range is undifferentiated.
The range positions are selected by a floor-mounted shifter.
The case is a two-piece aluminum case which contains the following components:
| • | A planetary gear assembly |
The drive chain connects and operates the drive sprockets.
The planetary gear assembly contains the following components:
| • | A three-pinion planetary carrier |
The planetary gear assembly provides the four-wheel drive range when
engaged.
The reduction ratio is 2.72:1 in this range.
Identification
An identification tag is attached to the rear half of the transfer case.
The tag provides the following information:
| • | The transfer case model number |
| • | The low range reduction ratio |
The information on this tag is necessary for servicing this transfer
case. If the tag is removed or becomes dislodged during service operations,
keep the identification tag with the unit.
Power Flow
Input torque is transmitted to the transfer case gear train through
the transfer case input gear. This transfer occurs in all drive range positions.
Torque transmission in 2HI range occurs as follows:
| • | Torque is transmitted from the input gear to the range shift hub
and the mainshaft. |
| • | Torque flow continues through the slip yoke. (The slip yoke is
splined to the mainshaft.) |
| • | Torque flow continues to the rear propeller shaft and axle. |
In the 2HI range, the mode synchronizer remains in the neutral position
and does not lock the drive sprocket to the mainshaft. As a result, torque
is not transferred to the driven sprocket.
Torque transmission from the input gear to the mainshaft is the same
in the 4HI range. However, in the 4HI position, the mode synchronizer sleeve
is shifted into engagement with the clutch teeth of the drive sprocket. This
locks the drive sprocket to the mainshaft through the synchronizer. The drive
chain then transmits the torque through the drive sprocket to the driven
sprocket. Since the front output shaft is splined to the driven sprocket,
torque flows through the output shaft to the front propeller shaft and axle.
This results in high range four-wheel drive.
In the 4LO range, the range shift hub is shifted into engagement with
the planetary carrier. This causes the input gear to rotate the planetary
pinions inside the annulus gear. The planetary carrier, range shift hub,
and mainshaft rotate at a gear reduction ratio of 2.72:1.
