The 4 wheel drive on my 1999 grand Cherokee is not working. it makes a noise like parts is falling off

2003 grand cherokee ! WJ body. jeep.
why not take it to a real shop and ask them to find the true cause.
in our shop we have an electronic stethoscope ( a $50 tool) t
that finds causes, easy.
and for sure LOCATION. (if R/F then it is., so look only there)
bad wheel bearings, bad rotors. bad brakes, caliper guides seized.
loose hub nuts.
bad shock. or falling off>?
cracked wheel. damaged suspension parts, loose ball joints.
a good mech, can flex these parts, parked.
and find what is loose? find one, or go to a suspension shop
or a pro brake shop.
NOISE, only moving?
only bouncing?
only under power ?
only coasting?
in any gear. ?
only turning.?
what?? hopeless for me to guess, id be hands all over car.
see why posting here is useless, reason, we cant drive it and hear it.!!! there are 3000 parts on the car, any can make noise.

see suspension here.
http://www.jeep4x4center.com/knowledge-base/index.htm?utm_source=cj#service

You need to be more specific. To start, which 4 wheel drive system your jeep has? (Select Trac, Quadra Trac II or Quadra Drive)
Then: does it never work, or only in 4-Lo?

A few parts should be interchangeable. Most of them will not be however since the Grand Cherokee underwent a complete re-design for 1999. Some engines and transmissions will switch out. The rear axle in the 97 was commonly a Dana/Spicer 35. This was replaced with a larger rear differential in 1999 for increased towing capacity. The wheels should interchange ok, power steering system was pretty much the same and as long as the hydraulics (supports) on the hood are the same length they should work

sounds like the transfer case is broken.

I hava a 1999 Grand cherokee loredo V8 with full time 4wheel drive. when the rear tires slip I am hearing a poping noise in the front end when the 4wheel drive engages. I was told by one person that it could be the chain in the transfer case slipping but I was told by a jeep salesman that this year jeep did not have a chain. Could this be the CV joints in the front axels?

the direction is take your car in to a service shop and have pull the wheel off and find out whats wrong???????

it sounds like you have a promblem in the tranfer case

There's a technical bulletin on that from Chrysler....The power steering lines need to be replaced. I have the same problem as you see this link - http://www.wjjeeps.com/tsb.htm#STEERING

SUBJECT:
Steering Honk On 4.0L And 4.7L LHD Grand Cherokee Vehicles
OVERVIEW:
This bulletin involves the replacement of the power steering pressure
and return hoses and tube.
MODELS:
1999 - 2002 (WJ) Grand Cherokee (Domestic and International Markets)
2001 - 2002 (WG) Grand Cherokee (International Markets)
NOTE: THIS BULLETIN APPLIES TO 1999 - 2000 4.7L AND 1999 - 2002 4.0L
GRAND CHEROKEE VEHICLES THAT ARE LEFT HAND DRIVE (LHD) AND
ARE NOT EQUIPPED WITH HYDRAULIC COOLING.
SYMPTOM/CONDITION:
Some vehicles may exhibit a honk-like sound from the power steering
system. This sound occurs most often during a low speed right hand turn,
as would occur during parking lot maneuvers.
DIAGNOSIS:
If the customer indicates that the above condition is present, perform the section of
the Repair Procedure that is appropriate for the equipped engine.
PARTS REQUIRED:
Qty. Part No. Description
1 04883077 Fluid, Power Steering (MS-5931 quart)
1 05080950AA Hose, Pressure (4.7L)
1 52088116AB Fitting, Pressure Hose - Quick Connect At Pump (4.7L)
19-005-02 -2-
Qty. Part No. Description
1 05080951AA Hose, Return (4.7L)
2 **06504502** Clamp, Hose (4.0L or 4.7L)
1 **52088452AE** Hose, Pressure (4.0L)
1 **52088774AC** Hose, Return (4.0L)
1 **52088775AB** Tube, Return (4.0L)
6 **34201631** Rivet, Plastic Black (Front Fascia - 4.0L)
1 **06102141AA** Screw, Pressure Hose (6 mm - 4.0L)
REPAIR PROCEDURE:
**IF VEHICLE IS EQUIPPED WITH A 4.0L ENGINE:**
1. Remove the front fascia panel.
Fig.

universal joint on the driveshaft may do this !
check transmission fluide as well.
good luck

Sounds like cv joint on axel is bad. install new axel A.S.A.P. Before it breaks or comes apart.