Question regarding TT4 system

[sluggish]

So my TT4 light has been on in the truck for a long time now(since I bought the truck, actually) and though the truck seemed to be working fine and would go wherever I needed it to go, I know suspect there is an issue. From what I have read, it is supposed to be a pretty good system. Here is what happened.
 
While on the trail, I snapped the bolts connecting the right rear axle to the diff. No big deal, tie the axle up so I can limp home without it damaging too much underneath. I should still have 3 wheel drive anyway. This is partially true, I had left front wheel drive but not right, and had no rear at all. Made it interesting getting back to the main road but managed to make it out after some winching in the tough spots. Got the axle bolts and back rolling on the trail but still things are not right. I got myself stuck in a couple very easy spots that no 4x4 should ever get stuck. Luckily I was alone and trying a few positions to take pics, so there was nobody else to witness it. Honestly it would have proven very embarrassing to be stuck where I was sitting. I basically only had left front and right rear working for me and both of them were about 2 inches off the ground. I stuffed a log under one and drove away but otherwise I was just freewheeling there.
 
My conclusion is that something computer-wise must be acting up(why the light is on) and is preventing the system from functioning properly. I was under the assumption that the other 3 wheels would work in an AWD system. Somebody please advise me if I am out to lunch or is something actually wrong here. My ABS light is also on and I have discovered that it is a wire that has worn through. Is it likely that the two are related, seems that they would be to me but this thing is new to me so I'm looking for educated input here. Thanks.

[Roy]

Now, you need to come out on a few off roading events and have the older fellows chat you a little.
Even a TT4 system can be BTM ed. That is , hold your foot on the brakes and apply steady fuel--1500-2000, to conditionally load up the diffs and allow 4 wheel lockup. The TT4 system works if you hold a steady 1500ish, when light is off, then the brake sytsem acts like traction control in reverse. The system will overheat after about a minute of heavy TT4 use, let it cool and system will be ready again.
Hope to see ya at one the events.
 
Scratches in the paint are just memories of good times! Dents, well, good times with an advanced trail and sore knuckles from holding the wheel too hard.  (HOLY SHIT OBSTICALES) 

[Roy]

Just found out what you do---- Hummer Tours--- . Maybe a weekend up at Kevins Playground will answer all your questions!
This event is Mid November.  Come on out and have some uncharted fun.

[sluggish]

Yeah mine doesn't see anything but work use, but it does need to be kept up to do that. Not likely I'll get the truck out to many(if any) events. Especially since they are likely on weekends and that's my busiest time. I just want to make sure the truck is working like it is supposed to. Plus I want to add some more obstacles and terrain and be sure I can actually get through it.

[Roy]

You can always go to full lockers  --air or electric !

[sluggish]

I'm starting to lean that way. I'm hoping that may help a bit in the winter too so I can maybe avoid putting the chains on the tires. Where is the best place to buy lockers for these?