2004 Jeep Liberty. the transfer case engauges into 4 wheel drive with no problems. sounds like everything is working ok. But when dissengaging back into 2 wheel drive it dosnt like to dissengauge. sometimes it will sometimes it wont. it seems to work better on snow but even then sometimes it wont. also if it dosnt there seems to be a loud whinning noise. is this common it didnt seem to do this when it was new. i would apprieciate any help you could give me. and thank you !!

SOURCE: Unusual noise

Not really a "solution" but this may move you a step closer to one...Check vacuum operated servo blend motors on the heater box. I would disconnect and plug the vacuum supply line to the dash controls (on the engine side of firewall) and drive it for a while. Obviously, if it's cold out you may not want to do this till summer because heat will not work, but it's worth a try, just to get a location on the problem isolated without taking the entire car apart!!

SOURCE: 4x4 wont work in a 97 jeep

The only Solution to this is 1 of 2 Things ! The Shifter Linkage is Off of the Transfer Case 2 The Transfer Case is Shelled out and needs to be Rebuilt. Check underneath on the Transfer case for any Noises when in 4X4 and Check the Linkages. Please Rate my Response, I need all the Help That I can Get! Thanks!

SOURCE: Quadra Trac II 4 wheel drive problem

Oil is added to transfer case through a plug usually located about half way up the back of the case.
When making a diagnosis, a good tech relies upon previous experience matching that to known symptoms, then upon teardown to verify his ideas. A good working knowledge is essential so the tech can picture in his mind what is happening inside the unit.(i once knew an old tech who could sit in the shop office and make a correct diagnosis as another tech drove a vehicle into the shop) That's rare, but there are good people out there! Your coupler may have to be removed, but that largely depends upon what the shop sees and feels.
Good luck

SOURCE: 4 wheel drive doesnt work.

Has this Jeep been modified at all?
It sounds like the shifter cable was reinstalled backwards.
Specifically the 4-Low "Not Climbing Well". 4-Low should give you the best torque and hill climbing ability.
Do you feel any "Binding" in the steering wheel (difficult to turn)?
Remember a Jeep uses real driveshafts and differentials to give you 4WD - you cannot engage 4WD or 4-Low on dry hard surfaces. It needs a little bit of slip between the wheels for turns.
Check you're fluids too.

SOURCE: 2004 jeep liberty stuck in 4 wheel drive low -

a reluctant transfer case can sometimes be coaxed by shifting into reverse, backing up 10 feet, and then back to forward.