1987 chevrolet s10 4wd automatic transmission. 4wd low is perfect, 2wd and 4wd high drives 100 to 500 yds then pops into neutral and grinds gears.Any adjustment?Can you dend exploded parts breakdown?

On the transfer case
Transfer Case - Electronic Shift
The four-wheel drive electronic shift-on-the-fly feature electrically shifts the vehicle transfer case between 2WD, 4WD HIGH, and 4WD LOW. The system mode is selected by the operator through the mode select switch (MSS) on the instrument panel. The operator is informed which mode the system is in by two instrument cluster indicators: one for 4WD HIGH which appears as 4WD, and one for 4WD LOW, which appears as 4WD LOW. Shifts into 4WD HIGH can be made at any speed. When shifting into 4WD HIGH with the vehicle stationary, tooth blockage may occur preventing shift completion. When the vehicle is driven above 8 km/h (5 mph) the shift will complete. When shifting in or out of 4WD LOW, the four-wheel drive (4WD) control module requires that the vehicle speed be less than 5 km/h (3 mph), the brake pedal be applied, and the transmission be in NEUTRAL (automatic transmission) or the clutch pedal be depressed (manual transmission).
The gearmotor encoder assembly is mounted externally on the transfer case. It drives a rotary cam which moves the mode fork and range fork within the transfer case between the 4WD HIGH, 4WD LOW, and 2WD range positions.
The four-wheel drive (4WD) control module controls the gearmotor encoder assembly that shifts between 4WD HIGH, 4WD LOW, and 2WD modes.

I'm assuming you're talking about the transfer case popping out of 2 high or even 4 high. It could be that the transfer case needs a chain or gears replaced and is slipping on the cogs/gears. In 4 low it takes less pressure/strain to move the vehicle so it doesn't slip. I would put the trans. AND transfer case in neutral, with the FRONT wheels blocked, and NOT running, jack at least one rear wheel off of the ground, and try turning the rear drive shaft back and forth to feel the free play (free play in the transfer case, not the rear end). Excessive free play should tell you that the drive chain/gears are very warn and could be slipping. That would be a start.

sounds as if your transfer case is gonna have to be inspected via inspection port for a worn or bent "finger" this is the thing that moves gears on shaft when pushed by 2wd/4wd handle/solinoid or a worn or broken pin "the thing gears slide back n forth on" this usually occurs after the vehicle has recieved a hard Jolt as in a minor fender bender , or your out crushing rocks on the trails all day and might have been just a little too hard on it on that last hill MAybe ? they just usually don\'t break or bend without a reason known to driver

the transmission and the transfer case are two different parts. the transfer case takes the shaft power and splits it to the front and back. depending on the cable or electric motor that shifts the transfer case gears. you could have a problem with just an electric motor or cable and or the transfer case it self could be the problem. try putting the truck into neutral before trying the high and low to make it easier to work and hope it goes. the second thing is are the rear wheels working in 2wd or in 4wd or is just the front wheels working in 4wd.

More than likely the shifter parts or worn out, rebuild it.

Whats happening is when you go into drive the transfer case spins but is not in gear and then when you go into park the gears are grinding, because the transfer case is spinning, its like trying to go into park while the wheels are spinning, the transfer case is in neutral you need to adjust it, and make sure the adjustment is right or you may be in 4wd low instaed of 2wd so after the adjustment check and postions of the 4wd.

Depends, do you have 4 wheel drive? If so you can just use 4 wheel high, or if things get really slippery, use 4 wheel low and go slow, both in the drive position on the transmission shifter.

If 2wd, just use drive and go slow, again, if it gets slippery out, you can shift down in gears to go slower and to keep your speed slow.

If you're talking about snow and ice on just streets, then stick with 4 wheel high with 4x4, or "drive" in 2wd. You typically don't want to switch to 3,2, or 1st gear at highway speeds.

If you're playing in the snow, just use 4x4 high until you get stuck, then switch to 4 low to get out.

The only time I switch gears with the transmission (from drive to 3,2, or 1) is when I want to go really slow and keep it there. However, when I "play" in the snow, it's Drive only.

Does this answer your question? If not, let me know! Thanks

Either your linkage is not properly adjusted or the shift fork is a bit worn inside the transfer case. I have a bit of wear on my own and shift into low range while rolling with no load, between 5&20mph and it works fine except that I need to anticipate needing it before hand. One important rule...If it grinds, don't force it into gear. That will cause damage.
Also, if you just got it, change the oil in there...you have no idea when it was last serviced.

shift fork min a newprocess tranfer case has a tenancy to wear in the case and wount stay in gear say [email protected] lets talk

check the rear dif.