02 chevy silverado 4x4 service light always on and stuck in 2 wheel drive.

SOURCE: My 1999 chevy silverado 1500 four wheel drive

You probably have a bad encoder motor.It is located on the side of the transfer case on the drivers side.It is black.The other problem they had with these was the switch but you have already replaced this so your next thing is the encoder motor.Hope this helps.Good luck.

SOURCE: 1994 chevy s10 blazer 4x4 push button type

small sylinoid on the top of the transfer case needs replaced. easy to do. it has three vacumelines going to it just trun out and replace like a bolt.

SOURCE: stuck in 4 wheel drive and wont come out.

hey there i cant tell you what you are missing but i can tell you how to disengage the front wheels . ok you have a vacum line that runs right under the battery and a line that comes up from the front diff. to the same place ( you may have to remove batt and batt tray to get full access to this) un bolt it and temporaly put batt and batt tray back in start it up and decompress this and see if it comes out .... you should here clunking noise if it goes back in ... if thats the case just pull that big vaccum line off .... to test get all four tires off the ground and have some one put it in drive but dont hit the gas it should turn on its own ...if that dont work check the cable that runs down to the differental

SOURCE: 2000 chevy silverado 4x4 doesn't work

vacuum switch needs to be replaced.

SOURCE: 4x4 quit working

Jack up the rear wheels and put it on jack stands. Have someone get in it and put it in 4wd and drive. Release the brake. Rear wheels are spinning only right. Don't get under it but look under it and see if the front driveshaft is spinning. If the shaft is spinning but the wheels aren't it is likely a bad front axle actuator. If the front shaft isn't spinning it is a transfercase problem.