Transfer Case Issues 2001 Tundra

Hello!
I recently purchased a 2001 Tundra 4x4. The previous owner had just replaced the 4x4 actuator on the transfer case. Before purchasing, I tested 4Hi and 4Lo, and everything seemed good.

Now I'm having a few issues about 2 weeks after the purchase. When I press the 4Hi button, the truck goes into 4Hi as it should.

But then when I go into 4lo I run into trouble. I put the truck in neutral and pressed the break, but when I push the 4lo button one of two things happens:

1) Most frequently, I hear a humming noise from the actuator area. Then if I put the truck in gear, the humming noise turns into a buzzing noise that sounds like plastic gears (in the actuator?) are grinding.

Or 2) The other thing that has happened less frequently is the truck acts like it's in neutral and there is not power to the wheels--front or back.

From what I'm learning, the transfer case has one system for turning 4x4 on/off, and another system for turning low range on/off. Apparently the 4x4 system is working. In 4Hi I can see the drive shaft to the front differential turning. But apparently the transfer case is having difficulty shifting from high range into low range.

I understand that there is a "neutral" position between high range and low range, and this would explain why the truck sometimes gets stuck without any power to any of the wheels when it's trying to make the shift.

My guess is that the transfer case is what caused the old actuator to go bad. And now that we have a new actuator, it sounds like the transfer case may be ruining the new actuator as well.

I do not know if the transfer case fluid has ever been changed. My initial guess is the the 4x4 on this truck has not been used much, and that the transfer case fluid is getting old and sludgy. This would explain why the actuator apparently keeps burning up trying to engage low range.

These are my current thoughts, but I wanted to get any thoughts from those of you who have more experience with this!

Appreciation

 

My 2010 Tundra is experiencing similar problems. It's equiipped with a dash mounted switch to select 2H, 4H, and 4L. It will go into 4H and operate correctly. It no longer goes into 4L. I took it to my dealer for troubleshooting. I was told it could be a an electrical problem or the solenoid itself. And it would cost me approximately $1500 for them to tear it down and find out. Furthermore, I was told that any time I attempt to place it in 4L there is a risk it could get hungup in neutral leaving me without any drive at all. Very scary considering the places I go that require 4L. Its a lot of money for something I would use maybe six times a year. I also don't have high confidence in what I was told, and plan to take it to another dealer. Meanwhile its 2-HI or 4-HI. Hoping your post will bring answers to both of us.

 

Just a heads-up: You're in the 2000-2006 subforum, and I'm not sure you have the same transmission as we do.

I was just about to ask, "You know you need to be in NEUTRAL and have 4HI LED solid before you can get into 4LO, right?!" then I realized ... wait! Those instructions may not be the same for a 2010.