2001 S10 stuck on 4 Lo

Seems a know issue and is the Transfer Case Motor or Module.

https://www.google.com/search?q=2001+Dodge+Durango+is+stuck+in+4+hi

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Go under the vehicle and check the four wheel drive linkage.

the switches may be bad they are easy to replace

2001 Chevy Blazer it likes to stay in 4 low. replaced sensor, pannel motor, older computern to check it was placed for a couple weeks or less it will do the same thing again. Just dies and quits has to be restarted agin still in 4 low . Tried to shift the gears slowly, Place in reverse and 2HD pressed and held while backing up this dinn't work either. To get it home I had to hold it in neutral and run the gears again ginally I got it to a shop. He is out of ideas too.

sounds like the 4 wheel drive
switch in the transfer case is bad.

your high low range shift solenoid is out!! change it!

It could be a bad cable going to it. Check under the battery tray and see if that cable and actuator is operating properly. Could also be a bad encoder motor.

Just to clarify, the "transmission" is not stuck in 4-Lo. It is the "transfer case" that is attached to the transmission that actually engages the 4-Hi and 4-Lo modes. To properly shift your vehicle into 4-Lo, you know that you have to shift the transmission into neutral and slow down to less than 5 mph. Once your vehicle slows down to this range, your can switch your transfer case into 4-Lo mode. Due to the inner workings of the transfer case, the actual shift into 4-Lo may take a few seconds to complete. This is normal and does not signify that there is an issue. All transfer cases that have 4-Lo mode will act this way regardless of the make or model. To make a long story short, to shift out of 4-Lo you must follow the same steps that you took to shift into 4-Lo, just in reverse order. Switch the transfer case to 4-Lo mode if it isn't already there. Slow down to less than 5 mph (your vehicle must be moving, though). Then, shift your car into 4-Hi or 2WD. Give your vehicle several seconds to complete the shift. The transfer case indicator light will flash until it is complete. When it does complete the shift into the new gear mode, you will most likely hear a "clunk" (the range sleeve inside the transfer case disengages from its mating spline) from under your car. Again, any transfer case with 4-Lo (regardless of make or model) will exhibit this same noise. This should help you get out of 4-Lo. It is good practice to shift your car into and out of 4-Lo at least a few times each year to keep all of the splines free of corrosion and build-up. Based on the age of your vehicle, your transfer case may also need a complete flush and some new transmission fluid. Hope this helps.

It should tell you on the Shifter whether or not that you can Shift on the Fly. Check the Manual first if there is one in the Truck. Some Models had this and some Did not. Was an Extra from Factory Option.

i believe those are vacuum controlled on top of the transfer case is a plug with 3-4 vacuum lines going to it,you will need to take it out and see if the check ball is stuck if it is it needs to be replaced