I think I've read all the relevant post on this topic but still uncertain as to what my solution may be.
It's a 98 Jimmy with 3 button system. If it's in 2HI, it shifts perfectly to 4HI. I can then shift to 4LO, and back again to 4HI. But it does not then shift back to 2HI. Eventually, after rocking the truck and pressing the 2HI button, it will shift back. Sometimes takes 10+ minutes of trying. So you can imagine, I hate to use the 4WD, but sometimes need it.
Here's the thing. I can hear the TC shifting as I press the button, but then appears to shift back again and end up staying in 4HI. I read a post about the encoder motor on the TC being bad. But it shift fine between Hi and Lo. Is there really a "shift" involved between 4HI and 2HI? Is this shift really one to change the vacuum position, to de-activate the vacuum to the front diaphram up front?
I jacked up the front end of the truck when it was stuck in 4wd and with the engine off, I am able to spin the front wheel. Started the truck up, vacuum was applied and the wheel would no longer spin.
I've been trying to figure out what's wrong with this for a long time. The dealer said they'd recommend replacing everything in the system. About $1800. No way I'm spending that. Thanks for any advise you may have.