Why does my 99 Chevy S10 keep jumping out of 2wd into 4wd? It don't want to go back into 2 wd with the yellow light lit?

i think you have to back up 40 feet to shift it out. do this in shift mode of 2 wd and 4wd.

GMC and Chevy has issues with the dash controls on 4WD models

I have a 97 chevy s10 4x2. I also have a winding sound coming from the same area. I believe it could be one of two things or both, water pump, power steering pump. keep in mind depending on the size motor you have, the 4.3l vortec wich is what I have and the v8 has a natural winding sound to them in that area. you will know a difference when that winding sound becomes more of a needed replacement part. good luck

There are a number of different hub systems so this may not work but it has worked for me on both auto and manual locking hubs. On a flat surface without traffic. Put the trans into neutral, shift the transfer case into 4x4, shift the trans into reverse and back the truck up 15-20 feet. Completely stop and shift trans into drive. See if this has locked the hubs in. If not, you can also try following the same instructions except shifting into 4wd low. Sometimes the hubs need a "bump" to get them to slip into place. Keep In mind that if the 4 wd low select works, you need to shift it back into 4 wd high before continuing! When taking the truck out of 4wd to 2wd, I recommend the same, shift to neutral, select 2wd, back truck up, shift back to drive and check. Its entirely possible that your hubs need maintenance (they're often overlooked) but hopefully this will get you going. Please let me know if thus worked or if I can offer other suggestions. Good luck!

I would say that it is probably the buttons themselves. I had problems with my 99 doing this too.

put truck in reverse back up 20 feet then try shiftn it then into 2wd.

With any 4WD like this, always move a few feet in the opposite direction when disengaging. If you were moving fwd in 4wd, switch to 2wd, back up a few feet, then go fwd.

sound like problems in transfer case shift module.

what causes the 4wd to kick in when you have it in 2wd

Well,it depends on the facilities you have to work with.Hand tools versus air tools.Professional car hoist,or jackstands and a floor jack.You also did not specify 2wd or 4wd,as a 4wd has 2 driveshafts versus one for a 2wd...etc.You also didn't specify automatic or manual trans.Generally speaking,with the facilities i have at work,and air tools,transmission jack,etc.For a 2wd truck,about 1- 2 hours to remove,and 2-3 hours to reinstall.For a 4wd truck,about 2-3 hours to remove,and 3-4 hours to reinstall.Now that's presuming the truck is from down south and not all rusted up,because rusted bolts adds considerably to labor times,and makes a set of torches mandatory.These times i have quoted are coming from an older man that's slowing down some.In my prime years,i could remove a 2wd trans from your truck in about 30 minutes,so,the time is relative to ability too.