Won't stay in 2w or 4w high

Year/make/model/engine size???

they have a transfer case motor . these typically sieze up

you have 4w low.. low/lock..4w high and hi lock..4w low is just a slower set of gears that gives the truck way more power for like pulling or towing in harse conditions.. 4 w hi is more for traction at hyway speeds..you may have a seperate lock lever.. most do..

just replace the switch.

Probably broke your U-Joints on your driveshaft, preventing the rear wheels from turning. Your driveshaft might have disengaged from your differential too. check underneath concentrating on the driveshaft and differential

my 2000 4w drive mitsubishi io 2w drive light is flashing while in 2w drive

look at the driver side visor the shift pattern is printed there. it should be also on the shift lever itself . I think 2 wheel high is all the way forward then back 1 is neutral back 1 more is 4w low and all the way back is 4w high

the linkages are out of adjustment.

For 4W Hi either be stopped or moving at a slow rate of speed (<20 MPH) and move your 4WD selector to the 4 Wheel Hi position.

For 4W Lo stop and move the selector from 2W Hi to 4W Hi then push down on the selector and move through N into 4W Lo.

My 94 did the same thing. In a automatic, you have to come to a full stop, it usually grinds when in 4L ,And for the shifter, I had to look at mine, 2w is all the way forward to the dash, then 4H is toward you 1 click, and "N" is the next toward you, then 4L , you have to push the lever down and pull backwards. Always come to a full stop when changing gears and wait a few seconds before changing direction.