Do you have a diagram for NP246 transfer case

what vehicle are u working on

i would plug it into a diagnostic unit and it will tell you whats wrong

take it too a garage unless you have the cable and software

If you go to autozones website and make a free account, you can logon to that account and put in the year, make and model of your car and look for the free repair diagrams. They have the wiring diagrams. Then change the make and model year to the donor car and look for those diagrams.

LEAK AT TRANSFER CASE COMING FROM DIFFERENTIAL PINION SEAL OR THE TRANSFER CASE SEAL LEAKING.YOU CAN GO ON LINE TO ON LINE AUTO REPAIR MANUAL ON AUTO DATA MANUALS YOU SHOULD BE ABLE TO FIND TRANSFER CASE DIAGRAM BUT YOU HAVE TO PAY TO USE SITE FOR 3 TO 6 MONTHS.

http://personal.utulsa.edu/~nathan-buchanan/93fsm/transfer/15componen.pdf
Try this and let me know if it works....I can get a few more diagrams

https://www.fleet.ford.com/maintenance/owners_manuals/default.asp
owners manual is here . it has fuse box diagrams inside it

Depending on which transfer case you have, there will either be an electronic actuator or a vacuum actuator that engages the front differential. On the backside of the transfercase there should be a round metal tag bolted to the case. It will have a number on it that starts with NP. Either an NP241, NP246, etc. This will tell you which case you have. Grab a repair manual at an autoparts shop, and it will show you the location of the actuator for the specific case you have. If you have a vacuum actuator, check the vacuum lines going to it first before replacing it. Twelve years does a number on rubber vac lines under a vehicle. You may just have a leak in one.

I have 2K bravada. Make sure you have serviced your transfer case with the "blue" GM Auto-trac II fluid. The "encoder" motor is a common failure item also. Unplugging it at the transfer case should cause the "service smart trac" light on dash to appear. This tells you that probably the encoder controller is good. Only buy the GM/Delphi/AC Delco motor, or you'll be changing it often. Try "thepartsladi" on eBay!

You will end up destroying the transfer case, The transfer case is electronic and not mechanical as the older ones and the speed sensors will throw off the transfer case, if you lose traction to the rear end in the rain, snow or around a corner. The transfer case may activate and deactivate and without the front drive shaft could result in the transfer case to literately explode, also know as grenade. At that point, your looking at a transfer case and may be a transmission. You van runs on RWD unless the rear wheel start to lose traction and then the encoder motor activates the transfer case turning your astro in too a AWD. This was done to save gas, the older AWD transfer case was casing the idle arm to wear out prematurely and the gas economy was 17 MPG and the new AWD system that you have brought the van to 22 MPG. Why do you want to remove it??? if you do i guess you can disconnect the wire harness to the Encoder motor to the transfer case. Good luck and keep me posted.

I have seen this problem on many gm trucks including my own 1999 chevy tahoe with the NP246 transfer case model the rear out put bearing has a plastic cage the falls apart and or the clip holding it in place shatters causing this noise you can inspect this by removing the rear drive shaft and with a flash light look into the transfer case tail shaft to see if every thing is intact. also this type of transfer Case is known for the drive chain to stretch and hit the inside of the case housing start by checking the bearing first.