4WD Problem

I have an 05 TB with 4WD. Until recently, it worked exceptionally. A couple of months ago, I noticed the switch lights would blink or not light at all the next time I started and drove after using the 4WD. I took it in and the dealer put in a new switch.
Last week I went out again and got stuck in relatively light mud. My buddy in a Jeep said only one of my wheels were spinning in 4Hi and 4Lo. I managed to get out of the area by putting it into AWD. Only then did the 4WD seem to kick in when needed.
I took it in to the dealer and they explained it was working fine and switched it into 4Hi and 4Lo right there. I told my story and the mechanic told me there is no locking differential and that tire spin is normal.
Is this true? If so, why bother having 4WD if only one tire spins?
Please help.

It is possible to spin one frt and one rear wheel in 4wd with no locking rear diff, 4wd is really one ft and one rr wheel driving the vehicle. If you spun only the rear in the mud that's another story.

Im not sure if I had one from the front and one from the back spinning. Pretty sure it is just one tire overall spinning. It also doesnt explain why I get better traction in AWD than 4Hi or 4Lo. Seems to me the AWD engages, but the 4WD does not. The light blinks and then switches, but I just dont trust my TB anymore.

The dealer just tells me they hooked it up to the computer and everything reads fine. Is there something else I/they should check?

Get the truck on a slippery surface and get someone to watch the wheels and see if the front and rear spin, that is one way to confirm 4wd without going thru jacking it up and such.

A great simple idea, much too non-complicated for me to come up with on my own. lol. Thanks. Ill try it after the weekend.

I had the problem with the 4WD switch light blinking or not coming on at all on my 02 TB. It could be your encoder motor is going bad, there was nothing wrong with my switch when I pulled it out and inspected it. I disconnected the battery and when I reconnected and started it worked fine. It could be you need to reset, but with the other sympton you mentioned, it sounds like your encoder motor.

Welcome to AF, good info but this thread is fairly old to continue.

You're right, I didn't realize that. I was looking for a thread concerning a nuisance problem I'm having where I can feel a heavy vibration and resistance when I try to turn hard left sometimes. Doesn't seem to do it to the right.