With 60,000 miles and never used to 4 wheel, the one time I needed to use 4wd to back out of a ditch, the transmission slipped in drive. I had to use 2nd or 1st gear to get it to move. Once up, now only 1 and 2 gear work, not 3 or Drive unless I move it to 3rd once in motion but it will slip if I accelerate too fast. And, there are funny mechanical noises coming from near the front wheels. No lights are on, fluids are full and I am not so happy; any ideas from someone with a car repair brain?
Do you know the transmission model in your truck, i.e. 4L60-E likely? Hopefully, Transman618 will spot your post and have an idea. He is pretty good with diagnosis of GM transmissions.
Have you had the problem looked at? What needed to be done? What broke? This is curious problem and I would like to find out what it was. TNX