Cant Engage 4WD 98 GC

[bhnz]

Hi Team , Have just brought a 1997 Grand Cherokee Laredo, 80,000km . Has the 4L 6-cyl engine and runs really nice.

How on the central pannel it only shows as been in 2wd ( rear wheels on the little car picture are green ) , When I stick it from 4WD - 4wd-lo it changes to yellow but still only the back wheels are lit. So decided to park on a grassy hill and see . Definatly 2wd , back wheels spin , nothing up front .

Any ideas on why this is ?

 

[SteelHeadz]

There are 2 types of t. case offered on your 98 GC. their features are as follows:The NV249 is an on-demand 4-wheel drive transfer case with two operating ranges and a neutral position.

Operating ranges are 4-high and 4-low. The 4-low range is used for extra pulling power in off-road situations.

Engine torque is distributed to the front and rear axles through a viscous coupling. Nearly all the available engine torque is directed to the rear wheels during normal driving situations. when slippery conditions are encountered, the variable viscous directs torque to the front wheels as necessary. The NV249 low range is provided by a gear reduction system for increased low speed, off-road torque capability. This range is designed for temporary use only.

The NV242 is a full and part-time transfer case It provides full time 2-wheel, or 4-wheel drive operation.

A differential in the transfer case is used to control torque transfer to the front and rear axles. A low range gear provides increased low speed torque capability for off road operation. The low range provides a 2.72:1 reduction ratio
NV242 Transfer Case

The input gear is splined to the transmission output shaft. It drives the mainshaft through the planetary gear and range hub. The front output shaft is operated by a drive chain that connects the shaft to a drive sprocket on the mainshaft. The drive sprocket is engaged/disengaged by the mode fork, which operates the mode sleeve and hub. The sleeve and hub are not equipped with a synchro mechanism for shifting.

The geartrain is mounted in two aluminum case halves attached with bolts. The mainshaft front and rear bearings are mounted in aluminum retainer housings bolted to the case halves.

OPERATING RANGES
NV242 operating ranges are 2WD (2-wheel drive), 4x4 part-time, 4x4 full time, and 4 Lo.

The 2WD and 4x4 full time ranges can be used at any time and on any road surface.

The 4x4 part-time and 4 Lo ranges are for off road use only. The only time these ranges can be used on hard surface roads, is when the surface is covered with snow and ice.

 

[bhnz]

MIne Definatly has FullTime 4wd - N - 4WD-LO .

Im thinking that coupling is notkicking on the front wheels.

On the center console the little car picture has its back wheels green but not the front. Should I assume that If i really get it climbing the gravel the front will light up green when the transfer case kicks the fronts in ?

 

[Bounty__Hunter]

Could be as simple as the 4wd indicator switch on the transfer case. Follow the wires to the transfer case.

You have the craptastic 249 transfer case, it's common for the viscous coupler to go bad.

A 231 transfer case is a good common upgrade to get better reliability and 2wd. I build a lot of 231's to fit GC's.