I have a 99 jeep grand cherokee limited with a 4.7 with quadra track and the 4wheel drive is not working... works in 4 low but not in all time any answers would help

WJ jeeps.
what mode? 4h, 2l lock >?
why not just drive it and get it all loose and happy first.
get the gearlube hot, see if it wakes up, i bet it does.
there is no vacuum hose. that is part time. used long ago.
vacuum ended in 1995 with command trac.
the newer cars the front axle is cut out, inside the transfer case front end. ending vacuum and now electric.

Select track (stay off dry pavement in 4wd)
Quadra-Trac-II NV 247 Gerodisc system 1999+
Quadra-Drive NV247
if quada stay out of low or lock.

read this page,. and discover what you have.
or go under car, see that transfer case, see that silver and red tag
that is the NV number. what is yours>?
we can not guess options. ever.

http://en.wikipedia.org/wiki/Jeep_four-wheel-drive_systems

which one of 4.
http://www.wjjeeps.com/tcases.htm

Possibilty... Check to see it is switching between the two hi to low low to hi.

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?

You probably have Quadra Drive. Your problem comes from lack of limited slip additive in the differential fluid.If the fluid was changed a long time ago, you better change it and add the limited slip additive. If it was changed lately, then just add the limited slip additive. Drive some tight figure 8 s after the fluid change, to let the additive work into the vari-lok differentials.
Sometimes the problem is a low fluid level in the T-case, so check that out as well.

a bad wheel speed sensor or not matching tires

Could you tell me what selection you have on your 4x4 shifter?

You have 4 high (full time) N 4 Low and nothing else?

Quadra only sends power to the front axle when it is needed, it uses a hydraulic unit that senses slip then send power to the front.

You also need to make sure your getting it in to gear right, for me I found that getting to 4 low can be hard as they tend to bind, move the 4x4 shifter to N take your foot off the brake and pull it into 4 low, do the same getting back out.

I have owned every 4x4 Jeep T case in Grands from 93 to 02 they offer fantastic traction and options and are strong.

Make sure your T case fluid is full, if you have never changed it DO SO, as dirty fluid plays hell on them, if you do have Quadra trac you need to get the correct fluid for the case, go to your Jeep dealer and get it, DONT put trans fluid in as this dose not work right with the system.

If you want "Locked" run the system in 4 low, as heavy off road in 4high with Quadra is not the best for heavy off road, use 4 low to that.

If you need more help just ask, I hope this worked.

1993 2HI N 4LO, 1998 5.9 LX Quadra trac with limited slips 2000 2HI, 4HI full 4HI part N 4LO 2002 Limited with Quadra with Vari-Lok differentials.

the link for the 4wheel drive pops off the trany, get under the jeep and push it back in,, you may need to get a new clip,, not hard to do

1st let me make sure I understand your Jeeps 4 wheel drive. I believe the quadra trac system is a full time 4 wheel drive, there is no 2 wheel drive setting, only a separate 4 Lo (for very slow speed). If this is correct, the problem is, the quadra trac system you have is supposed to compensate for any variations in wheel speed, whether it's driving in the snow, or cutting the wheels sharply to park on dry pavement. What u describe is typical behavior of a part time 4 wheel drive system. The problem is, your full time 4x4 should be compensating for this, and it's not. So, let me know if the above info about your 4wd is accurate (no part time 4wd setting, no 2wd setting, only full time 4wd and 4Lo setting. If it is, the system is not compensating for changes in the wheel slippage correctly.