Transfer Case: Description and Operation

General Information
The NV231HD and NV241LD are part-time transfer cases with a low-range gear system. They provide three operating ranges plus a Neutral position. The low range position provides a gear reduction ratio of 2.72:1 for increased low speed torque capability. Operating ranges are: 2-high, 4-high and 4-low.
The gear cases, retainer and extension are all of aluminum. Drive sprockets and an interconnecting drive chain are used to transmit engine torque to the front/rear propeller shafts. The mainshaft, input gear and front output shaft are supported by ball and needle bearings.

Operating Ranges
Transfer case operating ranges are:
- 4x2 (2-wheel drive)
- 4x4 (4-wheel drive)
- 4 Lo (4-wheel drive low range
The 4x2 range is for use on any road surface at any time.
The 4x4 and 4 Lo ranges are for off road use only. They are not for use on hard surface roads. The only exception being when the road surface is covered by ice and snow.
The low range reduction gear system is operative in 4 Lo range only. This range is for extra pulling power in off road situations. Low range reduction ratio is 2.72:1.
A front axle disconnect system is used to achieve two-wheel drive mode. The axle disconnect vacuum motor is actuated by a vacuum switch on the transfer case. The switch is operated by the transfer case range rod.

Shift Mechanism
The transfer case is operated by an adjustable floor mounted shift: linkage. The transfer case shift lever is directly attached to the shift sector. The sector operates the range and mode forks within the transfer case.
A straight line shift pattern is used with a neutral detent. Lever range positions are imprinted in the shift knob.