No 4WD , any advice is welcomed!

Hey all, I drive a 2006 DC Tundra SR5 4wd(not no more)

So my 4wd is pretty much fried to the point where I had to take off the fuse responsible for to keep it in 2wd. To put it in perspective, a few months back during a rainy period in NC, I had to trek some pretty deep mud/waters for my job and did it with ease. However, on one of the last passes through the mud it was really being stubborn on going back to 2wd, so I had to play with it by rolling it back and forth, turning it off and on and pressing 2wd/4hi repeatedly. I didn't think much of it since it was the first occurrence. Then, after two weeks, I had to return back to the mud and this time trying to get back to 2wd was much worse. I did the same procedure but this time when I got it back in 2wd and started heading home, and around 30-40 mph, I heard the heart wrenching grinding of metal right below me. I stop immediately to check it out. I see that the vent line connected to the outside of the T-case actuator corroded off. I knew that isn't good. Water must have gotten in there but the question is how long was it like that? There wasn't much I could do but to get home so I get right back on, this time there was no grinding of metal. I knew I couldn't afford to have to anything worked on so I set the problem aside and told myself not to use the 4wd till I can have a look at it. Months go by and now its time to go to the beach. The other day I wanted to check if it'll work and no, 4Hi will not lock in. 4Hi and 4Lo buttons are flashing constantly at the same time that not even turning the truck on and off will reset it. But turning it off and on will somehow-randomly- put on 4Hi. So I had to fight it to get it back into 2wd, turn it off, disconnected the battery and removed the fuse for it.

Edit: Also I'm not sure if this was always here and I just noticed or if it just started by this mishap but everytime I start the truck, there is a single 'clunk' sound coming from underneath the truck. Like something sliding and smacking another thing. Other than that, the truck is 'fine'

Apologies for the long story. I suspect I got water in the actuator through the small vent hole and fried it, so replacing that is pretty high on my list. Are there other possibilities for this type of behavior? Could I have gotten water in my T-case aswell? I have so many questions. Thanks for hearing me out.

 

I’m guessing the actuator is bad. Should definitely drain & fill both diffs and the t case. Probably should drain & fill the transmission too. Any water or milkshake looking oil will give you a better idea of what’s going on inside.

Good luck!

 

As for the clunk, check the rubber exhaust hangers. I’ve had them come loose. But you might need to be underneath and have someone start it up to try & locate the noise.