Leastbay

Yesterday I put my truck in 4hi when I was going through a little patch of slick mud. As soon as I turned the switch the check4x4 light came on but it shifted in and out fine a few times with just the light coming on. I tested it when i got home and everything was working properly with no check light. I decided to try again this am and when I switched to 4hi the whole truck jerked and it shifted to 4 lol somehow I was able to get back to 4x2 from neutral. What is the most likely culprit? Solenoid or transfer motor